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The original item was published from 9/10/2021 10:21:27 AM to 10/30/2021 12:00:01 AM.

News Flash


Posted on: September 10, 2021

[ARCHIVED] The City of Napa’s Water Division Provides Update on Water Supply and Quality

Water Update

The drought is real; and we thank you for partnering with us to reduce water usage by 20% from last year’s water use. Reducing outdoor irrigation to 2-days per week is making a difference. Please keep it up and transition to shorter run times and then to 1-day per week as the days get shorter and the nights cooler.

The City of Napa’s drinking water supply is completely reliant on surface water from local reservoirs, Lakes Hennessey and Milliken, or the Sacramento-San Joaquin Delta via the State Water Project. With the below-average snowpack affecting the Delta’s water availability and our local reservoirs extremely low due to below-average rainfall, it is critical for everyone to actively reduce their water usage so the City can deliver uninterrupted drinking water to our customers throughout the drought.

To preserve both the water supply and the water quality, City Staff are aggressively managing our source water and optimizing our water treatment operations. Even with our current water usage reduction, we need to use local Lake Hennessey water to supplement the State supply. On Sunday, September 12th, the City will switch to Lake Hennessey as our primary supply for the next 3 to 5 weeks.  

As is typical in fall, some customers may observe different tastes or odors that can be described as earthy, musty or moldy. With Lake Hennessey’s water level already abnormally low, these tastes or odors may be heightened.

The City recognizes the changing aesthetics of the drinking water, which is common with surface water supplies. With increasing temperatures and direct sunlight, Lake Hennessey experiences seasonal algal blooms that impart some taste and odor to the raw water. The taste and odor changes are not unique to Napa’s water sources as seasonal algae blooms are common to many surface waters. As algae dies off, they release odor causing compounds.  Although the water treatment process removes the algae, compounds that cause an unpleasant odor can be detected, resulting in aesthetically different drinking water at times. Throughout the water treatment process, the water is regularly tested and the drinking water is verified safe to drink.  

As we manage through the current drought, the City of Napa wants you to know it is our highest priority to always provide safe and reliable potable water. Please visit our website for water-related information and to learn more about your City of Napa water system and conservation efforts. If you have a water quality concern or other questions about your water service, we encourage you to contact us directly at 707-257-9521.  

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