West Lake Sammamish Water Pressure

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Project Banner 6-20-17.jpg

The city is planning a project to improve water pressure along West Lake Sammamish Parkway, tentatively in 2021-2022. A recent study found that the pressure in the water system along the parkway is lower than it should be. In addition to ensuring there is enough water flow for normal household uses, adequate pressure in the city’s public water system is important for two reasons:

  1. it helps to make sure that there is enough water to fight fires, and
  2. it helps reduce the water quality risk that potentially contaminated water could enter the water system during a water main break or fire event.

Before we increase pressure in the water system, we are requesting that customers in the red highlighted area on the map below to please complete a survey to assist us in project planning. These downhill areas have higher pressure, and the survey will help us to understand if your plumbing is protected from high pressure.

West Lake Sammamish Water Pressure Project Map

Frequently asked questions

Bellevue Utilities may need your help in two ways. First, we need you to verify if you have a pressure reducing valve (PRV) and an expansion tank installed. Depending on the elevation of your house, this equipment may be required by plumbing code to protect your home and appliances from damage. A typical PRV is shown below and could be installed outside near your water meter, or inside near your home shut-off valve, in a closet, or your garage. An expansion tank is shown below (circled), and is most likely installed next to your water heater.

Second, depending on your elevation, we may ask you for permission to measure the system pressure outside your house (at an outdoor hose connection). This may help confirm whether or not you have a PRV, whether it is in working condition, and the current setting of the PRV in case adjustment is needed. If we do measure pressure, you would be notified at least 48 hours in advance.

Typical PRV
Expansion Tank and Water Heater

If plumbing code requires you to have this equipment (either now or after the improvements), this project could result in installment of a PRV at your property if you don’t already have one.

The proposed increase in pressure could cause damage to your home if your house is below an elevation of 90-feet and you do not have the protection required by plumbing code. It is important to the City that you are aware of these changes, and that damage to your home does not occur.

Yes. Over one third of Bellevue’s water customers are affected by this plumbing code requirement (pressure greater than 80 psi), and homeowners and businesses frequently need to install individual PRVs.

The city has many different pressure zones to ensure that we meet minimum pressure requirements. Within each zone the pressure varies according to ground elevation. As a practical matter, Bellevue’s varying topography means that we have a wide range of pressure within each zone. If your house is at a lower elevation within a zone (especially if it is below the street), then you are more likely to have high pressure, even if there are areas with low pressure nearby.

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