Retention / Detention Ponds


During or after heavy rainfall, the Sewer Division fields many calls regarding detention / retention basins that are on or near homeowners’ properties. Please read the following information, which should help answer many of your questions:

  • These basins are designed to hold excess storm run-off water and release it at a predetermined rate to slow the runoff and minimize flooding. The rate these basins discharge water is designed to be slow, and you cannot usually see it over a short period of time. Most basins will take 24 to 48 hours to drain.
  • These basins are required by law. Releasing these waters prematurely is illegal and could cause flooding for other property owners further downstream in the drainage system. These basins are designed with an overflow area to prevent the water level in them from rising too high and damaging adjacent property.
  • The proper functioning of the restrictors in these basins must be assured by proper inspection and maintenance, which the Sewer Division tries to perform one or two times each year.
  • These restrictors are typically rather small. They can be as small as a one inch by two inch slot and are easily clogged by landscape debris, wood mulch, and other materials. Please consider this if a detention/retention basin is in your yard or adjacent to your yard and minimize any type of material which could wash away or float during a heavy rainstorm and block the restrictor.
  • Please wait a minimum of 24 hours after a storm to call us regarding a lack of discharge from any pond, unless there are extenuating circumstances.