Water officials in White Rock believe they have found the source of the E. coli contamination at the root of a prolonged boil-water advisory.

Three more positive coliform samples were discovered over the weekend, and after sampling each of the city's wells and all of the water lines that led to the reservoirs, it was discovered that the Merklin reservoir had the highest level: two counts per 100 millilitres.

Now, the process has begun to pump the 1.2 million litres of water out so that experts can sample the bottom of the reservoir and begin the cleaning process.

EPCOR, the private company that owns White Rock Utility, has been in charge of the city's water for the past five years. It comes from a groundwater source called the Sunnyside Uplands aquifer and is provided through six different wells. The water then goes directly to residents without further treatment.

White Rock is one of the few municipalities in the Lower Mainland that does not disinfect its water, and this has sparked debate about whether the city should consider chlorination.

The mayor of White Rock, Catherine Ferguson, doesn't think changes to the water supply need to be made, but admits the decision will be out of her hands.

"The residents of White Rock feel very strongly about their water. They don't want to chlorinate it. I believe we have some of the greatest water anywhere, but I do believe this conversation will take place with Fraser Health, EPCOR and the city."

Randy Christensen, a lawyer for Ecojustice, would like to see the provincial government take action and pass regulations that ensure White Rock's water system is repaired and that all systems are required to provide safe drinking water.

"Having a good strong set of laws will give people confidence that they can turn on their tap and drink their water without having to worry about it, without having to boil it, without having to run it through their own personally installed filters."

Currently in British Columbia, there are only binding water-quality standards for three types of contaminants -- one of those is coliform-type bacteria, including E. coli.

Christensen points out that there are a number of contaminents that are not subject to legally binding standards in B.C. and that includes arsenic, which has previously been found in the White Rock water supply.

This year marks the 10th anniversary of Canada's worst waterborne disease outbreak in Walkerton, Ont., where 2,500 people became ill from E.coli bacteria, and seven people died from the infection.

With a report from CTV British Columbia's Leah Hendry