Tap water contaminants, when present, come from pipes- not water suppliers
By Nancy Needham nancy@theacorn.com

Some residents may be confused after reading the results of the latest test run on the city's water, information that was included in their water bills.

So, is it safe or not?

The quality of the city's water supply meets all of the state and federal maximum allowable contaminant levels for safe drinking water, said Mark Watkins, public works director.

Sounds good- but not so fast. The tests showed actual tap water coming out of the faucets of Thousand Oaks homes did contain copper and lead, but those minerals aren't from the city's water supply.

There's no lead or copper in the service lines, but those minerals can be found in older pipes from residential taps owned by customers, Watkins said.

Customers concerned about levels of lead or copper in their water are encouraged to open their spigots each morning for 30 seconds or more before consuming the water.

The procedure, called "first flush," should lower the concentration of those minerals in the water, the city report said.

Every three years the city is required to test customers' tap water.

The water going through home pipes can leach off copper and lead from the customer's pipes, brass fixtures and soldered joints, but the water comes to the home without those elements, the report said.

Thousand Oaks has highquality water, Watkins said.

Still, low levels of the gross alpha activity emitted by uranium, the chemical element uranium and bromate, a byproduct of disinfecting drinking water, were found.

These elements cannot be removed by the best available technologies, and no healthrelated concerns make it necessary to do so, said the city staff report.

"Chronic toxic risk indicates there may be adverse effects that may develop gradually from low levels of chemical exposure that persist for a long time," the report said.

The maximum contaminant level goals for bromate and gross alpha activity are zero, the report said.

"Seawater influence on state project water in the Sacramento River delta has resulted in detectable levels of bromide," the report said.

Concentration levels in 2006 average about half of the state's accepted MCL.

Levels increased when ozonation, a process to destroy bacteria, was initiated in 2005, the report said.

Uranium is a naturally occurring radioactive element found in many ground and surface waters due to the element's presence on the earth's crust, the report said.

Reverse osmosis could lower the uranium and gross activity level in the water but would make the water more corrosive and could cause it to leach more lead and copper from residents' pipes.

Reverse osmosis could also raise the average customer's cost per year by $980 to $3,880. Eliminating gross alpha activity is difficult if not impossible, according to the report.

"Our water is in full compliance with the federal and state bromate limits," the report said.

In 1996, the state of California passed laws that dictated all water suppliers with more than 10,000 customers compile a report comparing water quality with the state's public health goals. These goals are currently unenforceable.