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Lehi Cityscape

Lehi City Implements PI Treatment Plan

Posted Category: Newsroom, Uncategorized.

Lehi City has created a treatment plan for the pressurized irrigation (PI) system. On Monday, August 21st, the Water Department shock treated two of our key reservoirs, with one receiving a steady rate of dosing. This treatment is designed to help deactivate and lower the levels of bacteria.
E. coli 0157 was found in the sediment of the Sandpit Reservoir, which is behind the Water Department. Crews shock-treated the Low Hills Reservoir and Sandpit Reservoirs, with Sandpit receiving a steady rate of dosing. The majority of PI water this time of year is delivered to the Sandpit Reservoirs behind the Water Department. This water is then pumped to other storage reservoirs to serve different parts of the city. The shock treatment in those reservoirs is a large, one-time dose meant to treat all the existing water in the reservoir. That treated water then leaves the storage reservoir and runs into the distribution system. The constant-rate dose then treats the water as it enters the reservoir.

PI water is not usually treated and tested. In the past, the Water Department has attempted to combat other species, such as Corbicua fluminea (Asian clam), with chlorine. Due to the quality of the PI water, the chlorine was ineffective. The City was advised to try a copper-sodium liquid solution to help treat the PI water. Crews will diligently conduct water sampling and testing throughout the next few weeks to measure the effectiveness of the solution. Even with the treatment, there is always a high chance of bacteria. The treatment will not get the PI water to the level and standard of culinary drinking water. This water was never meant to be consumed or played in.

Residents are asked to continue being cautious while using PI water.

  • Do not drink pressurized irrigation (PI) water (this includes pets).
  • Do not play in PI water.
  • Irrigation water should not be used for bounce houses, pools, slip-n-slides, etc.
  • Be cautious with uncooked produce from your garden. It is recommended by the CDC that you do not consume UNCOOKED produce from your personal garden at this time.

We understand that there are questions or concerns. For more information, visit the E. coli information page. Questions can be sent to,

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