Home Rain / Stormwater

Rainwater Quality—Appropriate Uses and Filtration

Rainwater Quality—Appropriate Uses and Filtration

Rainwater falls as a very pure water. Factors that can compromise its quality are contaminants picked up from the air, contaminants that have settled or fallen onto collection surfaces, and the physical properties of the collection surfaces and system components themselves.

Rainwater tends to be naturally “soft”, i.e. very low in dissolved minerals, which results in a taste that varies from more mineral-rich tap water. Rainwater is also slightly acidic, meaning that it can gradually dissolve heavy metals and other substances from the materials of the collection and storage system.

Debris that settles on roofs can include dust, pollen, bacteria, leaves, bird and animal droppings, dead organisms, and other organic matter. Even if the system is not intended to provide drinking water, these can clog pipes, causing algae growth and sediment buildup in the tank. First flush diverters, roof washers and sediment filters easily ensure that most of these contaminants do not get into the stored water.

Nevertheless, for drinking or bathing purposes, the water will need to be treated further with finer filtration and disinfection systems to remove or kill pathogens down to the size of viruses. Many countries, such as Australia, New Zealand, Israel and India, commonly utilize rainwater for drinking. RWH may provide higher quality water than supplies coming from saline or pollutant-laden rivers.

Please keep in mind that it is wasteful to use our limited energy and water resources to treat water beyond the needs of its end use, such as using potable water to flush toilets. (California Water Plan Update 2009, Chapter 16, "Matching Water Quality to Use", DWR) Making rainwater and graywater legal and safe for outdoor and indoor use is vital for maintaining California’s riparian ecosystems and water supply security.

Additional Information on Water Quality

Social sharing
back to top
Rebates and Incentives
side-monthly_feature-0310

Collection Potential

Roof/Catchment Area:
(sq ft)

Average Annual Rainfall:
(inches)

Gallons on average that you can expect to harvest:

Annual Rainfall

Find the annual rainfall in your city.

side-products_services

CALIFORNIA WATER EVENTS

Water Works
Sun Sep 05 @11:00AM
5809 Ayala Avenue, Oakland, CA
Regional Water Board Meeting
Wed Sep 08 @09:00AM
Elihu M. Harris Building, First Floor Auditorium, 1515 Clay Street, Oakland, CA 94612
Fundamentals of Grey Water Systems for Sustainable and Integrated Water Management - New Webinar
Mon Sep 13 @11:30AM
Webinar
Wholly H2o September Forum: Establishiing Baseline Water Use, Audits, Benchmarking
Mon Sep 13 @07:00PM
Jellyfish Gallery, 1286 Folsom (at Ninth St.) San Francisco, CA 94103 (corner of 9th and Folsom, Civic Center Bart)
Early Detection Monitoring for Quagga & Zebra Mussels
Tue Sep 14 @08:00AM
EBMUD San Pablo Bay Reservoir ,7301 San Pablo Dam Road, San Pablo, CA

Join the Wholly H2o Announcement List

Donate to Wholly H2o