A Review of Roof Harvested Rainwater in Australia

Waterborne Cryptosporidium species and Giardia duodenalis in resources of MENA: A systematic review and meta-analysis

This review explores our understanding of Cryptosporidium species and Giardia duodenalis distribution in Middle East and North African (MENA) water resources. Results emphasize that Cryptosporidium species (sp.) and G. duodenalis (oo)cysts are present in distinct categories of water in ten MENA countries. Cryptosporidium sp. proportional prevalence in the MENA region was 24.5% (95% CI 16.3-33.8), while G. duodenalis prevalence was 37.7% (95% CI 21.9-55.1). Raw wastewater and surface water were the water categories most significantly impacted. Both parasites were reported in the various types of MENA drinking waters. The most frequent species/genotypes reported were C. hominis, C. parvum, and G. duodenalis assemblage A. Despite the high prevalence of (oo)cysts reported, we should consider the absence of waterborne outbreaks. This indicates significant underestimation and underreporting of both parasites in MENA. Stakeholders should apply water contamination legislation to eradicate Cryptosporidium sp. and G. duodenalis (oo)cysts from water resources/categories.

Quality of rainwater and reclaimed water used in buildings and selection of appropriate indicators

OBJECTIVES

The use of alternative water sources such as rainwater or greywater (i.e., wastewater excluding water from toilets) for non-potable purposes may save water but, on the other hand, can also pose health risks to users. The main health risks come from microorganisms (such as bacteria, viruses, fungi, and protozoa). This work aims to analyse especially microbiological quality of rainwater and greywater used inside buildings in detail and to expand the existing knowledge about the potential health risks associated with these alternative water sources. It also considers methodological problems during E. coli and coliform bacteria detection. The final objective is to discuss requirements and appropriate indicators for monitoring recycled water quality.

METHODS

We examined 30 buildings with non-potable water systems in the Czech Republic and analysed a total of 137 samples of rainwater and 120 samples of greywater. From these 30 buildings, eleven, 5 of which used rainwater and 6 of which used greywater, were sampled regularly for 1-2 years for basic chemical parameters, various faecal indicators, C. perfringens, Legionella spp. and P. aeruginosa. Occasionally, samples were analysed also for the presence of environmental mycobacteria, amoebas, viruses, and selected pathogens.

RESULTS

Nearly three quarters of rainwater samples contained the faecal indicators E. coli or enterococci, or both, and in samples from several buildings also Clostridium perfringens was repeatedly detected. Untreated and treated rainwater were in respect to microbiological quality similar, suggesting that treatment processes were not very efficient. In greywater samples, beside faecal indicators, also P. aeruginosa and thermotolerant amoebas were repeatedly detected. Treatment technologies used for greywater were more efficient than those for rainwater systems.

CONCLUSION

Based on the results we evaluated appropriate indicators for monitoring recycled water quality and drafted the first Czech regulation for non-potable water.

Patterns of contamination and burden of lead and arsenic in rooftop harvested rainwater collected in Arizona environmental justice communities

As climate change exacerbates water scarcity, rainwater harvesting for household irrigation and gardening becomes an increasingly common practice. However, the use and quality of harvested rainwater are not well studied, and the potential pollutant exposures associated with its use are generally unknown. There are currently no federal standards in the United States to assess metal(loid)s in harvested rainwater. Project Harvest, a community science research project, was created to address this knowledge gap and study the quality of harvested rainwater, primarily used for irrigation, in four environmental justice communities in Arizona, USA. Community scientists collected 577 unique rooftop harvested rainwater samples from 2017 to 2020, which were analyzed for metal(loid)s, where arsenic (As) concentrations ranged from 0.108 to 120 μg L^-1 and lead (Pb) concentrations ranged from 0.013 to 350 μg L^-1 and compared to relevant federal/state standards/recommendations. Community As and Pb concentrations decreased as: Hayden/Winkelman > Tucson > Globe/Miami > Dewey-Humboldt. Linear mixed models were used to analyze rooftop harvested rainwater data and results indicated that concentrations of As and Pb in the summer monsoon were significantly greater than winter; and contamination was significantly greater closer to extractive industrial sites in three of the four study communities (ASARCO Hayden Plant Superfund Alternative site in Hayden/Winkelman, Davis-Monthan United States Air Force Base in Tucson - Pb only, and Freeport McMoRan Copper and Gold Mine in Globe/Miami). Based on models, infrastructure such as proximity to roadway, roof material, presence of a cistern screen, and first-flush systems were not significant with respect to As and Pb when controlling for relevant spatiotemporal variables; whereas, cistern age was associated with Pb concentrations. These results however, indicate that concentrations vary seasonally and by proximity to industrial activity, not by decisions made regarding collection system infrastructures at the individual home level. This study shows that generally, individuals are not responsible for environmental contamination of rooftop harvested rainwater, rather activities and decisions of government and corporate industries control contaminant release.

Microbial Characterization, Factors Contributing to Contamination, and Household Use of Cistern Water, U.S. Virgin Islands

Households in the United States Virgin Islands (USVI) heavily rely on roof-harvested rainwater stored in cisterns for their daily activities. However, there are insufficient data on cistern water microbiological and physicochemical characteristics to inform appropriate cistern water management. Cistern and kitchen tap water samples were collected from 399 geographically representative households across St. Croix, St. Thomas, and St. John and an administered survey captured household site and cistern characteristics and water use behaviors. Water samples were analyzed for Escherichia coli by culture, and a subset of cistern water samples (N = 47) were analyzed for Salmonella, Naegleria fowleri, pathogenic Leptospira, Cryptosporidium, Giardia, and human-specific fecal contamination using real-time polymerase chain reaction (PCR). Associations between E. coli cistern contamination and cistern and site characteristics were evaluated to better understand possible mechanisms of contamination. E. coli was detected in 80% of cistern water samples and in 58% of kitchen tap samples. For the subset of samples tested by PCR, at least one of the pathogens was detected in 66% of cisterns. Our results suggest that covering overflow pipes with screens, decreasing animal presence at the household, and preventing animals or insects from entering the cisterns can decrease the likelihood of E. coli contamination in USVI cistern water.

Distribution and temporal variability of uranium and toxic metal(loid)s in snow and rainwater from an oil industry and urban area in Thessaloniki-Greece

The concentrations of uranium and nine elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in snow and rainwater samples were determined. Samples were collected in Thessaloniki-northern Greece in three sites, one in the industrial area close to an oil production power plant and two in the centre of the city. Snow samples were collected during January-February 2019 and 2021 whereas in the case of rainwater, a two-year survey has been performed during 2019 and 2020. The activity concentrations of the uranium radioisotopes were measured by alpha spectrometry whereas the metal(loid)s concentrations were determined by inductively coupled plasma mass spectroscopy (ICP-MS). The elevated concentrations of uranium (U) and the deviation of the isotopic ratio of U-234/U-238 from the equilibrium value indicated intensive dissolution of uranium. The results were analyzed using statistical analysis (Shapiro-Wilk, Friedman and Kruskal-Wallis tests). The obtained data and the calculated enrichment factors (Efs) denote variation of the concentration values between industrial and urban area and different elemental distribution influenced from anthropogenic contributions, meteorological conditions and the COVID-19 pandemic.

Socio-psychological determinants of Iranian rural households' adoption of water consumption curtailment behaviors

Dealing with a growing population and a shortage of drinking water is a major challenge for politicians and planners. A key factor in ensuring a sustainable water supply is water conservation at the household level, which can increase productivity and save water resources. Therefore, promoting water consumption curtailment behavior will contribute significantly to reducing the global water crisis, especially in arid and semi-arid regions. Water consumption curtailment behaviors depend on individuals’ encouragement to choose and adopt voluntary behaviors and cannot be enforced by any political or planning power. In order to encourage water conservation those social and psychological factors should be considered that influence individuals to participate or adopt water consumption curtailment behaviors. Therefore, the study of factors influencing rural households' water consumption curtailment behaviors is of great importance. This study aimed to describe the socio-psychological factors influencing water consumption curtailment behaviors among rural households in southwestern Iran. The extended theory of planned behavior (ETPB) was used as a theoretical framework in this study along with descriptive norms (DN), moral norms (MN), habits, and justification. Data were collected using a questionnaire and analyzed using structural equation modeling (SEM). The results showed that ETPB can explain 35% and 54% of intention and water consumption curtailment behaviors among rural households in Iran. Our findings may assist policymakers in reducing domestic water consumption.

Community-Scale Rural Drinking Water Supply Systems Based on Harvested Rainwater: A Case Study of Australia and Vietnam

Rainwater harvesting (RWH) systems can be used to produce drinking water in rural communities, particularly in developing countries that lack a clean drinking water supply. Most previous research has focused on the application of RWH systems for individual urban households. This paper develops a yield-after-spillage water balance model (WBM) which can calculate the reliability, annual drinking water production (ADWP) and benefit–cost ratio (BCR) of a community-scale RWH system for rural drinking water supply. We consider multiple scenarios regarding community aspects, including 150–1000 users, 70–4800 kL rainwater storage, 20–50 L/capita/day (LCD) drinking water usage levels, local rainfall regimes and economic parameters of Australia (developed country) and Vietnam (developing country). The WBM analysis shows a strong correlation between water demand and water supply with 90% system reliability, which allows both Australian and Vietnamese systems to achieve the similar capability of ADWP and economic values of the produced drinking water. However, the cost of the Vietnamese system is higher due to the requirement of larger rainwater storage due to larger household size and lower rainfall in the dry season, which reduces the BCR compared to the Australian systems. It is found that the RWH systems can be feasibly implemented at the water price of 0.01 AUD/L for all the Vietnamese scenarios and for some Australian scenarios with drinking water demand over 6 kL/day.

Comprehensive evaluation of the possible impact of roofing materials on the quality of harvested rainwater for human consumption

Water is a vital natural resource that influences life and contributes to domestic and industrial activities. Availability and accessibility of safe water sources are crucial for a country's economic growth. Harvesting of roof runoffs is an alternative source of water used for domestic purposes. However, the quality of harvested rainwater can be affected by roofing materials. This research seeks to assess heavy metals concentration, physicochemical and bacteriological parameters in roof runoffs and estimate the water quality index and health risk these metals pose to consumers. Rainwater samples were collected from Aluzinc, Aluminum, Galvanized, and Asbestos roofing materials within the Ejisu municipality. Rainwater collected directly from the sky was used as control. All runoffs from the four roofing materials recorded Cd, Fe, Cr, turbidity, pH, E.coli, total and fecal coliform levels above WHO limit for drinking water. There was a significant variation in pH, EC, Zn, Cd, Cr, Fe, E. coli, total and fecal coliform levels between control samples and roof runoffs (p < 0.05). The estimated water quality index for runoffs from the four roofing materials exceeded 100 indicating their unsuitability for drinking. Cadmium recorded the highest non-cancer health risk to children and adults in all the roof runoffs. Hazard quotients (HQs) above one were recorded for a child (HQ = 40.1) and an adult (HQ = 13.6) via dermal exposure to Cd in runoff from Aluminum roofing material. Hazard quotient of 9.53 and 4.08 were estimated for a child and an adult respectively via oral exposure to Cd in runoffs from Asbestos roofing material. The estimated cancer risks were above 10^-3 for a child and an adult via oral and dermal exposure to Cd in all roof runoffs, suggesting a possible cancer health effect. The study concludes that the four roofing materials impact negatively on the quality of runoffs.

The Effectiveness of Rainwater Harvesting Infrastructure in a Mediterranean Island

Rainwater Harvesting system (RWHs) can be considered as an alternative water resource in the era of the climate crisis. This research aims to study the effectiveness of a RWHs for domestic non-potable use and the water demand of the community in a Mediterranean site (Chios island, Greece). A water balance model is applied to simulate the behavior of a rainwater tank and calculate the daily water savings. The analysis correlates rainwater tank capacity, catchment area and population. The operation of the rainwater collection system has been calculated for seven years. In order to assess the investment risk regarding the application of the RWHs, the financial ratio of PayBack (PB) period was determined. The multifaceted character of Rainwater Harvesting (RWH) practice in the three-dimensional concept of sustainability is discussed. This study concludes that RWH contributes to the greening of society, dealing with water scarcity in urban areas.

Virome in roof-harvested rainwater of a densely urbanized low-income region

Rainwater harvesting has been considered an affordable practice to supplement the conventional sources of water supply for potable and non-potable uses worldwide. This study characterizes the viral community found in roof-harvested rainwater (RHRW) samples obtained under different rain volumes in a densely urbanized low-income region in Rio de Janeiro, Brazil. Three pilot-scale standardized metal-sheet roofs (same catchment area, material age, and slope - 3%) were installed in the study area aiming at obtaining more reliable and representative samples. Fifty-four samples were collected from six rainfall events from January to April 2019 and concentrated by the skimmed-milk flocculation method. Pools of different rainfall volumes were submitted to high throughput sequencing using the shotgun metagenomic approach. Sequencing was performed on NextSeq platform. Genomic analysis of the virus community revealed that most are RNA non-human viruses, including two main families: Dicistroviridae and Iflaviridae, recognized for infecting arthropods. Bacteriophages were also relatively abundant, with a predominance of DNA phages belonging to Microviridae and Siphoviridae families, showing percentages from 5.3 and 3.7% of the total viral hits present in these samples, respectively. Viral genomic RNA viruses (77%) predominated over DNA viruses (23%). Concerning number of viral species identified, a higher percentage was observed for plant viruses (12 families, 58%). Hepatitis A virus and human klassevirus 1 were detected among the established human pathogens, suggesting the need for RHRW treatment before it is considered for human consumption. Australian bat lyssavirus was also detected, emphasizing the importance of environmental monitoring facing emerging viruses. The results corroborate the influence of the surrounding area on the rainwater quality.

Microbiological characterization of stormwater in a high-income neighborhood in Rio de Janeiro, Brazil

Stormwater harvesting and reuse in the urban environment is emerging as an alternative water source, despite human pathogens in the stormwater may represent a hazard to public health. This study presents the results of 1-year monitoring to evaluate the quality of stormwater obtained in a high-income neighborhood in Rio de Janeiro for a set of microbiological parameters as total coliforms, Escherichia coli (E. coli), human adenovirus (HAdV), human JC polyomavirus (JCPyV), Group A rotavirus (RVA), and norovirus GI and GII. Forty-eight stormwater samples obtained from two multiplex units presented total coliforms and E. coli in 91.7% (n = 44) and 58.3% (n = 28) of samples, while HAdV and JCPyV were detected in 20.8% (n = 10) and 12.5% (n = 6), respectively. Viral quantification ranged from 10³ to 10⁴ genomic copies/liter (GC/L) for HAdV and from 10¹ to 10⁴ GC/L for JCPyV. Neither RVA nor norovirus GI and GII was detected. Fifteen out of sixteen (93.8%) samples containing viruses were compliant as per fecal indicator bacteria (FIB) according to Brazilian standards for rainwater reuse and US EPA Guidelines for Water Reuse, suggesting that viruses monitoring should complement the study of bacterial indicators.

Desorption and Migration Behavior of Beryllium from Contaminated Soils: Insights for Risk-Based Management

Factors influencing the desorption, distribution, and vertical migration behavior of Be in contaminated soils are not fully understood. This study examined the desorption and migration of Be in a soil profile from a legacy radioactive waste disposal site using different batch leaching [monofilled waste extraction procedure (MWEP); synthetic precipitation leaching procedure (SPLP); simulated acid rain solution (SARS); and toxicity characteristic leaching procedure] and sequential leaching [community bureau of reference (BCR)] methods for insights relevant to the application of risk-based management. The results showed that Be desorption was higher in the presence of organic than the inorganic leachate composition (MWEP < SPLP < SARS < TCLP < BCR first-step). The desorption followed three diffusion control mechanisms, which resulted in three desorption rate constant estimates of 157, 87.1, and 40.4 Be/kg.h^0.5, and the estimated desorption maximum was 556 μg/kg. The desorption process was, spontaneous (ΔG > 0), enthalpically and entropically influenced. Increasing the incubation period and heat treatment resulted in a decrease of Be desorption and migration. The soil clay content and pH were the primary factors influencing Be desorption, and the results suggested that Be was desorbed from metal oxyhydroxides and surfaces of silicates (e.g., reactive surfaces of clay minerals), organic matters, and soil pores. Because of high K _d values, the mobility of Be was limited, and no exceedances of ecological or human health risk index or guidelines were determined for the current contamination levels at the site. However, Be released from the waste trenches has the ongoing potential to increase Be concentration in the soil.

On-site rainwater harvesting and treatment for drinking water supply: assessment of cost and technical issues

This study assessed the performance of rainwater-harvesting systems installed for selected public utilities in the northern provinces of Vietnam where rainwater was collected, stored in stainless steel tanks, and treated with a complex filtration unit and Ultraviolet (UV) disinfection system (full system). Results from an operation of over 5 years show that the untreated rainwater could not be used directly for drinking purposes as it was contaminated with bacteria (total coliforms TC = 200-300 CFU/100 ml, Pseudomonas aeruginosa PA = 40-160 CFU/100 ml), and turbidity = 2-4 NTU. Most of the heavy metals detected were found below the standard limits. Phenol and its derivatives were detected occasionally as higher than the standard value (1 μg/L). After treatment, all parameters met the drinking water standards. The capital costs of the rainwater systems were approximately US$200/m³ and US$180/m³ for a full system and simplified system (without complex filtration unit), respectively, while the operation and maintenance (O&M) costs were 3 cents/L and 0.8 cents/L on average for a full system and simplified one, correspondingly.

Removal of CX3R-type disinfection by-product precursors from rainwater with conventional drinking water treatment processes

In addition to surface water and groundwater, rainwater is used as an important drinking water source in many parts of the world, especially in areas with serious water pollution or insufficient water resources. Conventional drinking water treatment technologies can remove dissolved organic matter and therefore reduce the formation of disinfection by-products (DBPs) during subsequent disinfection using surface water or groundwater as drinking water sources. However, little information has been known about the effect of conventional water treatment processes on DBP formation when rainwater is used as drinking water source. This study evaluated CX₃R-type DBP precursors removal from rainwater by conventional drinking water treatments and the corresponding decrease of CX₃R-type DBP (trihalomethanes (THMs), haloaldehydes (HALs), haloacetonitriles (HANs) and haloacetamides (HAMs)) formation and toxicity during the subsequent chlor(am)ination. The result showed that both sand filtration (SF) and activated carbon filtration (GAC) were able to remove DBP precursors and GAC outperformed SF, but no DBP precursors removal was observed during coagulation-sedimentation treatment. Among all treatments, SF + GAC was the most effective for DBP precursors removal, with removal efficiencies of 64.2% DOC, 98% DON and 76.6% UV₂₅₄. Correspondingly, both SF and GAC decreased the formation of THMs, HALs, HANs and HAMs, and GAC performed better than SF. The combination of SF and GAC, especially SF + GAC, greatly decreased DBP formation, with average reduction of 79.2% and 85% during chlorination and chloramination respectively. After different treatments, the comprehensive toxicity risk of CX₃R-type DBPs was all reduced, among which GAC + SF exhibited superior performance. Generally, the main contribution of integrated toxicity was HANs during chlor(am)ination. The formation potential of THMs, HALs, HANs and HAMs and the corresponding integrated toxicity were greater during chlorination than that during chloramination. Therefore, the combination of GAC and chloramination was promising in mitigating the comprehensive toxicity risk of THMs, HALs, HANs and HAMs for rainwater.

The risk of cross-border pollution and the influence of regional climate on the rainwater chemistry in the Southern Carpathians, Romania

The aim of this study is the assessment of rainwater composition, regarding the various sources of major ions and heavy metals, taking into account the characteristic atmospheric circulations and the main air mass transport routes. Rainwater samples were analyzed for pH, electrical conductivity, major ions, and heavy metals. At all sampling sites, the most abundant anions were SO₄^2- and Cl-, while the dominant cations were Ca²⁺ and Mg²⁺. Regarding heavy metals, the dominance of Pb and Cd was found. The contribution of soil dust from the mining activities and the dissolution of CaCO₃, MgCO₃, and CaSO₄·2H₂O in the rainwater explains the high concentrations of Ca²⁺, Mg²⁺, and SO₄^2-. The overall precipitation contamination with heavy metals at the three sampling sites was assessed by the degree of contamination, showing that Pb and Cd presents the highest risks of all heavy metals. The values of toxicity potential suggested an elevated risk for human health in case of rainwater ingestion, especially in rural areas. Spearman correlation and PCA indicated that the chemical characteristic of the rainwater is primarily controlled by sources such as agricultural activities, mixed and crustal sources, traffic, and other anthropogenic, industrial influences, mining activities, smelting operations, coal combustion, and metal production.

Novel Bacteriophages Capable of Disrupting Biofilms From Clinical Strains of Aeromonas hydrophila

The increase in global warming has favored growth of a range of opportunistic environmental bacteria and allowed some of these to become more pathogenic to humans. Aeromonas hydrophila is one such organism. Surviving in moist conditions in temperate climates, these bacteria have been associated with a range of diseases in humans, and in systemic infections can cause mortality in up to 46% of cases. Their capacity to form biofilms, carry antibiotic resistance mechanisms, and survive disinfection, has meant that they are not easily treated with traditional methods. Bacteriophage offer a possible alternative approach for controlling their growth. This study is the first to report the isolation and characterization of bacteriophages lytic against clinical strains of A. hydrophila which carry intrinsic antibiotic resistance genes. Functionally, these novel bacteriophages were shown to be capable of disrupting biofilms caused by clinical isolates of A. hydrophila. The potential exists for these to be tested in clinical and environmental settings.

Comprehensive Assessment Methodology for Urban Residential Rainwater Tank Implementation

Rainwater tanks are increasingly being implemented as part of the integrated urban water management paradigm where all sources of water, including potable, stormwater and recycled, are considered eligible to contribute to the urban water supply. Over the last decade or so, there has been a rapid uptake of rainwater tank systems in urban areas, especially in Australian cities, encouraged through financial incentives, but more importantly, from change in residential building codes effectively mandating the installation of rainwater tanks. Homes with rainwater tanks in Australian cities have increased from 15% to 28% over six years to 2013. These building codes specify certain rainwater tank specifications to achieve a stated rainwater use, and hence potable water savings. These specifications include minimum rainwater tank size, minimum connected roof area, plumbing for internal supply for toilets and washing machines, and external supply for garden watering. These expected potable water savings from households are often factored into regional strategic water planning objectives. Hence if rainwater tanks do not deliver the expected saving due to sub-standard installation and/or poor maintenance, it will have an adverse impact on the regional water plan in the longer term. In this paper, a methodology to assess the effectiveness of a government rainwater tank policy in achieving predicted potable water savings is described and illustrated with a case study from South East Queensland, Australia. It is anticipated that water professionals across the globe should be able to use the same methodology to assess the effectiveness of similar rainwater policies, or indeed any other distributed water saving policy, in their local planning communities.

Arsenic contamination in rainwater harvesting tanks around Lake Poopó in Oruro, Bolivia: An unrecognized health risk

Drinking water sources used by largely rural and indigenous communities around Lake Poopó in the Bolivian Altiplano are impacted by drought and a combination of natural and anthropogenic mining-related contaminants putting the long-term health and sustainability of these communities at risk. As an alternative drinking water source, 18 rainwater harvesting tanks connected to corrugated iron roofs, each with a first-flush system, were installed in 5 communities around the lake. The water quality of these tanks was monitored over 22 months and compared to alternative unprotected surface and groundwater sources the communities previously relied upon. The rainwater quality was found to be within the Bolivian and World Health Organization (WHO) limits, except for elevated arsenic concentrations two times the recommended health limit (0.01 mg/L). Tracing arsenic concentrations through the rainwater flow-path showed that the elevated arsenic concentrations result from mineral dust particles entering the system when rainwater interacts with the roof catchment, with arsenic leaching out. A leaching test showed that 24 h of contact time between 200 mL of water and <1 g of roof dust is enough to raise the arsenic levels of the water above the Bolivian and WHO limit. Currently, no other research exists evaluating the quality of harvested rainwater in the Bolivian Altiplano for human consumption or the source of arsenic in harvested water. This represents a significant knowledge gap for future development practitioners and programs addressing water security around Lake Poopó and the wider region. As a result, it is strongly recommended to include arsenic as a standard parameter in water quality monitoring of rainwater harvesting projects, especially in active mining regions, and to optimize strategies to minimize roof dust from entering the collection system.

Microbiological Values of Rainwater Harvested in Adelaide

In Australia, rainwater is an important source of water for many households. Unlike municipal water, rainwater is often consumed untreated. This study investigated the potential contamination of rainwater by microorganisms. Samples from 53 rainwater tanks across the Adelaide region were collected and tested using Colilert™ IDEXX Quanti-Tray*/2000. Twenty-eight out of the 53 tanks (53%) contained Escherichia coli. Samples collected from ten tanks contained E. coli at concentrations exceeding the limit of 150 MPN/100 mL for recreational water quality. A decline in E. coli was observed in samples collected after prolonged dry periods. Rainwater microbiological values depended on the harvesting environment conditions. A relationship was found between mounted TV antenna on rooftops and hanging canopies; and E. coli abundance. Conversely, there was no relationship between seasonality and E. coli or roof and tank structure materials and E. coli. In several tanks used for drinking water, samples collected prior to and after filtration showed that the filtration systems were not always successful at completely removing E. coli. These results differed from a study undertaken in the laboratory that found that a commercially available in-bench 0.45 µm filter cartridge successfully reduced E. coli in rainwater to 0 MPN/100 mL. After running a total of 265 L of rainwater which contained high levels of E. coli through the filter (half of the advertised filter lifespan), the filter cartridge became blocked, although E. coli remained undetected in filtered water. The difference between the laboratory study and field samples could be due to improper maintenance or installation of filters or recontamination of the faucet after filtration. The presence of E. coli in water that is currently used for drinking poses a potential health concern and indicates the potential for contamination with other waterborne pathogens.