On September 23, tests showed an increase in coliform bacteria, resulting in a violation of a monthly federal drinking water standard – the first violation for DC WASA following 95 consecutive months of surpassing the standard.

This is Not a Health Emergency!

The Environmental Protection Agency , which regulates DC WASA, and the DC Department of Health are clear that the rise in coliform is NOT a health emergency.

Tests show no evidence of harmful bacteria in the distribution system we operate, but it is important that the media and our customers be notified of this new development.

What are coliform bacteria and why is this standard important?

Coliform bacteria are naturally occurring, widespread bacteria that originate in soil, vegetation and animals, and are generally harmless. Their presence in drinking water at certain levels means there is potential for more harmful bacteria to be present.

What caused the problem?

The EPA, the DC Department of Health, and the Washington Aqueduct say that the increase in bacteria is probably caused by the addition of orthophosphate – a chemical added to the water by the Aqueduct to help with the problem of lead leaching from service pipes and fixtures containing lead, and the warm summer weather.

The steps we are taking to deal with the issue.
We have successfully provided as much early notice as possible to customers, the general public, the media and local and federal government officials. WASA and the Washington Aqueduct (which treats and supplies drinking water to WASA for resale to our customers) are taking several important steps:

* Maintaining high disinfectant levels in the Washington Aqueduct drinking water treatment process.
* Informing the public with newspaper notices
* Contacting every resident with a direct mail program
* Accelerating unidirectional system-wide water main flushing
* Assessing and modifying, as appropriate, sampling program quality control/quality assurance methods

Sampling continues this month. Any changes to the level of coliform will be communicated to the public.