Irrigation & Backflow

Water demand increases sharply in the summer months, largely due to irrigation. Average daily demand during July and August is 10.76 million gallons per day (MGD), more than double the average winter month demand of 5.13 MGD.

The majority of sprinkler systems in Manhattan are scheduled to water on Mondays, Wednesdays and Fridays. This significantly increases water demand on those days and can place stress on the city's water system.

To spread the water demand throughout the week, please consider taking our irrigation initiative:
  • For even house numbers, water on Monday, Wednesday and Friday.
  • For odd house numbers, water on Tuesday, Thursday and Saturday.
This will take a little pressure off our water system on hot, dry days when we experience peak demand. There is not a water shortage.

For more information, contact our Public Works department at 785-587-4530 or download Take the Irrigation Initiative.
Monthly Water Demand
Typical Summer Week

Backflow Prevention

Irrigation systems are a common cross connection source. The city requires all irrigation systems in Manhattan to have a backflow preventer to reduce the likelihood of contamination of the public water supply. Backflow occurs when water in a distribution system flows in the opposite direction from what is normal. Hazards that require backflow preventers include fire sprinkler lines, lawn sprinklers, boilers and carbonated beverage dispensers. View more information about backflow prevention and cross connection.

Required Yearly Testing of Prevention Devices


While backflow prevention devices do a good job at protecting the water supply, they must be tested and maintained regularly to make sure they are in proper working order. The city requires yearly testing by a certified testing provider.

Testing providers can submit their test results online. To use this feature, testers must obtain a personal identification number (PIN) from the city by calling 785-587-4536 or by email.