Rainwater and greywater used for irrigation, plumbing, cleaning, utility systems, and cooling towers is considered a sustainable and economical alternative to potable water. Some studies predict it could reduce drinking water production by 7% and could possibly slow the depletion of groundwater reservoirs.

Reclaimed Water Safe? Think Again.

Considered cleaner than blackwater (wastewater from toilets), neither rainwater nor greywater is free of E. coli and waterborne pathogens like Legionella, the bacteria that causes Legionnaires’ disease. Water drained from showers, bathtubs, sinks, and washing machines (greywater) and rainwater collected from barrels and rooftops contain organic material and nutrients that promote microbial growth. Both sources carry health and environmental risks.

Environment for Pathogens

In a recent sampling of rainwater and greywater, Special Pathogens Laboratory found deadly pathogens including Legionella, PseudomonasStenotrophomonas and Klebsiella. Other studies show E.coli in both water supplies. Untreated or undertreated reclaimed water can cause gastrointestinal illness, pneumonia, and blood and skin infections. To date, one death from Legionnaires’ disease occurred from rooftop collected rainwater.

No Safety Guidelines

The World Health Organization recommends monitoring for fecal coliforms, but no federal guidelines exist to ensure the safety of reclaimed water. In 2004, the Environmental Protection Agency reviewed requirements by individual states, which include monitoring for indicator microorganisms and other waterborne pathogens. But only 16 states have adopted or implemented treatment or monitoring guidelines. To date, there are very few if any guidelines that provide treatment plans for detecting and controlling Legionella.

Test for Legionella, E. coli, and total coliform

Find out what's in your water. Special Pathogens Laboratory® offers a Water Reuse Panel (Coliforms: E.coli and Total (quantitative, Legionella culture and Heterotrophic Plate Count (HPC).  Advocates for prevention, we also provide a total water safety solution through SPL Consulting Services including: risk assessments and outbreak response, review of disinfection methods, water safety plans, and training.