Neglected Swimming Pools & Mosquito Control

Mosquito control and neglected pools
by Rob Cox July 16, 2014

Kern County, BakersfieldThe mortgage crisis of 2008-2009 left a lot of destruction in its wake. One unfortunate effect of the high number of foreclosed homes was neglected swimming pools. As payments became harder to make, pool owners stopped maintaining their pools, and when they moved out, the mortgage company, thousands of miles away and unable to effectively maintain the pool, also did nothing.

Consequently, this led to an increase in cases of West Nile Virus (WNV), and other such diseases, as mosquitos set up home in abandoned swimming pools. Mosquitos need only an inch of water to breed, and neglected pools, partially constructed pools left unfinished, or pools unable to maintain their water level due to water restrictions - also present a community hazard.

According to the Sacramento Mosquito Control District, just one neglected swimming pool can produce millions of mosquitos - infecting an entire neighborhood and putting your family and community at risk for West Nile virus. It's become a big issue in California, and other states where pools are more prevalent, such as Texas, Arizona and Florida. William K. Reisen, Entomologist with UC Davis that has studied an outbreak near Bakersfield, California concluded that abandoned pools 'can increase the spectrum of competent avian hosts, the efficiency of enzootic amplification, and the risk for urban epidemics'. Meaning, it's a serious health issue. 

PROBLEM: Unfiltered and unsanitized pools create a favorable breeding ground for mosquitos.


  1. Report any neglected or abandoned pools to your local mosquito control, usually a part of the health department. Wanted posters have sprung up in some parts of California's central valley, one of many efforts to encourage communities to report neglected pools. They really want to hear from you - pool owners, and pool service folks, so they can offer mosquito treatment and assistance to the home owner, even if the owner is a bank, thousands of miles away.

  2. If the pool cannot be maintained, or restored (see our earlier post on how to restore a pool neglected for years), there are some ways to control mosquito breeding.
  • Fairfax County, Va suggests treating abandoned pools with Mosquito Dunks, 3 in. round tablets that can be tossed in the pool to kill mosquito larvae.
  • The County of San Diego offers free Mosquito Fish at several locations. Add these live fish to your pool, and they'll eat the mosquito larvae.
  • Washoe County, Nevada suggests covering unused pools with a tight fitting mesh safety cover (keeping water level 6-12" below cover).
  • The Dept of Public Health of California suggests draining a pool, if it can be kept empty, but suggests consulting a pool service company to avoid potential problems with draining and leaving it empty.
  • Richardson, Texas officials note that pool covers should be pumped off (with automatic pool cover pumps).


West Nile Virus is a serious concern nationwide, don't let your pool or a neighbor's pool become a breeding ground for a disease which has been documented in over 40,000 cases, involving 1668 fatalities since 1999. (


- Rob