Demographics, practices and water quality from domestic potable rainwater harvesting systems

Abstract

In semi-arid regions experiencing rapid population growth, rainwater harvesting is becoming increasingly important. Roof-collected rainwater is the exclusive water source for many households worldwide. Improper collection, storage or treatment of rainwater can result in adverse health effects. This study surveys rainwater harvesting practices and examines water quality from these systems. At 36 households, stored 'pre-filtration' rainwater and 'post-filtration' water from the kitchen faucet used for drinking and cooking were sampled. Rainwater harvesters desire to conserve water and believe that rainwater is more healthful than surface or groundwater. Almost 95% of homeowners use filtration and purification devices, but 64% have never tested their water. Coliform bacteria were not found in any post-filtration water, but some pre-filtration water samples were high in total heterotrophic bacteria. Lead levels exceeded the United States Environmental Protection Agency (USEPA) standard of 15 μg L À-1 in 25% of pre-filtration samples and 6% of post-filtration samples. First-flush diversion devices significantly decreased the likelihood of pre-filtration lead levels above 15 μg L À1 . Aluminium, copper and iron exceeded USEPA recommended levels in a small percentage of homes. Although water from roof-collected rainwater harvesting systems was generally within drinking water standards, regular testing should be encouraged to avoid potential health problems.

Rainwater Harvesting as an Effective Climate Change Adaptation Strategy in Rural and Urban Settings

“…In terms of climate change, the use of rainwater harvesting for storm water management to prevent flooding (i.e. given the impervious fabric of urban settings) and the collection of rainwater for domestic use in drought-prone regions are among the most cited uses (Villarreal and Dixon 2005; Abdulla and Al-Shareef 2009; Stump et al 2012;Kim et al 2012). A recent case study from the city of Suwon in South Korea has shown that with government support and incentives for rainwater harvesting, it can be successfully integrated into urban contexts and prove very useful in increasing water capacities, reducing water bills, and preventing flooding (IRHA 2013).…”

“…Residents who use rainwater harvesting often indicate that they prefer the taste and softness of rainwater to well water as a potable water alternative. The majority of the rooftop rainwater harvesting systems are fitted with filtration (sand and/or carbon filters) and disinfection systems (ultraviolet or chlorination) to make sure the water collected in the tanks meets the national water standards (Stump et al 2012). Studies have shown that pollutants can be introduced into collected water from rooftops from organic matter, inert solids, faecal deposits from animals and birds, and trace amounts of certain metals from housing parts used in construction (Villarreal and Dixon 2005).…”

“…Studies have shown that pollutants can be introduced into collected water from rooftops from organic matter, inert solids, faecal deposits from animals and birds, and trace amounts of certain metals from housing parts used in construction (Villarreal and Dixon 2005). Stump et al (2012) study investigated 36 households in Texas that installed rooftop rainwater harvesting systems with capacities that ranged from 9 to 189 m 3 . The study found that with the existing filtration and disinfecting systems, collected rainwater generally met the USEPA drinking water standards.…”

“…The study found that with the existing filtration and disinfecting systems, collected rainwater generally met the USEPA drinking water standards. However, the study also found lead contamination to be a potential hazard from piping and atmospheric origins and recommended the frequent testing of rainwater if collected as a potable water source (Stump et al 2012). For this problem, EPA states that filtering devices certified to remove lead and other metals could be used to ensure potability of the collected water (1993).…”

“…This chapter presented case studies that illustrate the potential usefulness of rainwater harvesting to combat flooding and droughts in urban settings. Yet, a survey of the literature shows that the challenges remain, including contamination, backflow, lack of clarity in various rainwater management methods, uncertainty in calculating the benefits of the system, possible inflexibility of design criteria in ordinances, and the general lack of government incentives and knowledge in the installation and decision-making process for overall rainwater harvesting systems (Abdulla and Al-Shareef 2009;Kim et al 2012;Stump et al 2012). …”