City of Derby

Rain Sensors

In April 2008, the Derby City Council passed an ordinance requiring rain sensors in all residential and commercial automatic irrigation systems. Beginning May 24, 2008, rain sensors were required for all new residential and commercial irrigations systems. Residents who already have automatic irrigation systems (both well and city water) will be required to be in compliance with the law by July 1, 2009.

Read the Rain Sensor Ordinance.
View a rain sensor.

What’s a rain sensor?

A rain sensor is an electronic device that measures rainfall and interrupts the irrigation cycle. The sensor turns off automatic irrigation systems when a predetermined amount of rain has fallen. Sensors are mounted above ground in an open area outdoors in a location well-suited for gauging rain. According to the ordinance, rain sensors should be set to turn off the automatic irrigation system when 1/2 inch or more rain has fallen (although residents can adjust it to a lower setting).

Why is this being required?

As a public water supplier, the City of Derby is making water conservation a priority. Water is an increasingly valuable commodity that should not be wasted. The City of Derby encourages residents and business owners to be responsible water users.

How will it be enforced?

The Buliding Trades Official and Code Enforcement Officers will be responsible for ensuring that the new ordinance is being enforced. Once a rain sensor is installed, residents and business owners should fill out a form and City staff will keep a record on file. Remember, if you are a current resident or business owner, you have until July 1, 2009, to have your rain sensor installed.

Where can I buy a rain sensor?

Rain sensors can be found at most area garden centers. You may also research the different products available online. If you use a landscaping company, you may also ask them for assistance.

How much do they cost?

Rain sensors generally cost between $20 and $60. Installation can be performed either by the property owner or by engaging the services of a sprinkler system service provider. You may choose between a wireless or hard-wired rain sensor.

Advantages of a rain sensor

Conserves water: When installed on an irrigation system, a rain sensor prevents over-watering and assists with conserving water by reducing water that would be wasted if a lawn were irrigated and rained on simultaneously.

Saves money: The sensor will reduce utility bills by interrupting the irrigation system after 1/2 or more inches of rain has fallen.

Preserves irrigation system: Reduces wear on the irrigation system because the system will not run as often.

Protects the environment: Using a rain sensor will help protect surface and groundwater by reducing the amount of runoff that carries pollutants, such as fertilizers, into storm drains and groundwater.

If you have questions, please call the Water Department at 316-788-1424.

Questions or comments? Contact the Web Manager.