Possible Water Contamination in Small Area

Issued by the city of Redwood City

The city has issued a “boil tap water” advisory to approximately 150 residences and businesses due to possible contamination of the city’s water system in a limited area.

Occupants of most of the properties within the area bordered by Woodside Road, Virginia Avenue, Rosemary Lane, and Sierra Street are advised not to ingest tap water until testing is completed to determine if any contamination exists. Multiple tests must take place, and so results are not expected until late Sunday, September 18, at which time the city will notify the residents of whether they may ingest the water.

Included in this area are the and .

The potential contamination is the result of an un-permitted well that had been dug at a residence in the area, which had been inadvertently pumping untreated well water into the city’s drinking water system for approximately the last two weeks. An estimated 75,000 gallons of non-potable well water was injected into the City’s water system.

Upon discovery, the city immediately disconnected the well water system from its drinking water system, and commenced “flushing” the city’s water system in that area through fire hydrants in order to purge any remaining non-potable water. The water will be tested for coliform bacteria and E.Coli.

If the testing shows contamination, then the city would extend the “boil water” advisory and continue flushing, and would apply disinfectant (chlorine) to the water in the system in order to remove any contaminants.

The city became aware of the situation this morning when the resident with the un-permitted well called with concerns about a possible water leak.

Upon investigation, the city discovered the un-permitted well, and that it had been connected to the city’s water system. Apparently, this connection occurred two weeks ago when the resident had some plumbing work performed on his water system.

The city has used multiple methods of notifying the affected area, including its CodeRED emergency phone/email/text messaging system, and written notices posted at each property. The city will remain in contact with the affected area in order to provide them with updated information.