Water Conservation Guidance

Mercer Island is still facing a water shortage due to the Seattle Public Utilities (SPU) water supply line that is out of service. To ensure the City does not need to impose mandatory water restrictions, we are asking the Mercer Island community to make small changes in their daily lives to reduce water use.

We know many community members have started reducing water consumption at home, and the City is grateful for these efforts! However, the warm weather increases water consumption across the Island, and we all need to work together to keep our community safe.

If everyone makes one or two small changes, our collective efforts will help ensure the Fire Department has enough water supply to respond to emergencies this summer.

In addition to following general water conservation practices, the City is asking community members to take additional actions, such as:

• Water plants/yards no more than three times per week:
  • ODD numbered addresses water on Sun/Wed/Fri
  • EVEN numbered addresses water on Tues/Thurs/Sat
• Water early (before 10:00am) or late (after 8:00pm) in the day to reduce evaporation
• Let your lawn go dormant (brown)
• Postpone new planting until the fall when rain provides plenty of water for plant establishment
• Minimize vehicle washing
• Minimize refilling swimming pools and hot tubs
• Reduce shower time by two minutes
• Turn off water features, such as fountains

Additional water reduction measures can be found here.

You can monitor the City’s real-time water usage on our Water Usage Dashboard.

The City will keep the community updated about our progress and provide several days’ notice if water conservation guidance changes.

On May 1, 2024, the City Manager issued Proclamation No. 329 Declaring a Local Emergency due to the reduction in the supply of incoming potable water to Mercer Island caused by a leak in the Seattle Public Utilities (SPU) primary water supply pipeline to Mercer Island. SPU and City staff have been working to repair the primary water supply line, however given the highly technical nature of the repairs, work is not expected to be complete until late summer. The backup line will likely not supply enough water to keep up with the higher water demand typical during the summer months.

The City’s Water Shortage Contingency Plan (WSCP) provides guidelines to manage the water supply and consumption in the event of a water shortage. The plan enables the City to maintain essential public health and safety, and minimize adverse impacts on economic activity, environmental resources, and the City operations.

In June, the City anticipates activating the Voluntary Stage of water consumption reduction measures, as described in the WSCP. The WSCP identifies 28 actions that water customers can implement during the Voluntary Stage to significantly reduce water use – a combination of both behavior and hardware changes. The City hopes that by implementing these actions, entering the Mandatory Stage can be avoided.

Mercer Island City Council will receive a presentation of recommended actions in response to a water supply emergency at its regular hybrid meeting on June 4, 2024. Agenda materials for the meeting are available here (Agenda Item #11). The hybrid meeting will be broadcast live on MITV Channel 21 and live streamed on the City Council’s YouTube Channel.