Plug in tank causes excess pressure to as many as 37 Shorewood homes

As many as 37 homeowners in Shorewood could be submitting claims of damage to the city after excessively-high pressure caused relief valves on water heaters to blow off.

The Shorewood Public Works Department began receiving phone calls on Sept. 26 stating the Woodhaven water system was experiencing high pressure.

The pressure was so high that relief valves on water heaters blew off, as well as causing other plumping issues.

The high pressure was the result of a plugged valve in the Woodhaven tank.

When working properly, the tank is filled half with water and half with air. A well pump and air compressor maintains pressure.

If the pressure in the tank is too great, a pressure relief valve is supposed to be tripped, releasing the extra pressure.

Instead, city staff found that the pressure relief valve in the tank was intentionally plugged.

It appeared the plug has been in place for years, according to a memo written by Public Works Director Larry Brown.

It's unclear why the plug was installed.

When operating properly, the valve pops off at a pressure that is not much higher than the operating pressure, according to Brown.

Brown speculated that the valve could have been plugged because of a weak spring that began to leak. Instead of replacing the valve, it might just have been plugged.

The relief valve has since been replaced.

City Administrator Craig Dawson said there have been reports of flooded basements and other plumping complaints.

The city's insurance will cover the cash value of appliances or flood damage, not the replacement cost, according to Dawson.

At this point, Dawson said he is uncertain how much the claims could total.

Dawson said the city had previously researched abandoning the well because of issues with pumping capacity.

Shorewood staff is working with the city of Chanhassen to determine if it could connect into Chanhassen water supply for the neighborhood.