With school out and temperatures rising in San Ramon, nothing feels more like summer than a dip in the pool. Unless mosquitoes got there first.
Often hidden in the yards of foreclosed homes, neglected pools make the perfect place for mosquitoes to lay their eggs — quickly producing hundreds of these potentially disease-carrying insects. Officers from Contra Costa Mosquito & Vector Control District and San Ramon Code Enforcement have teamed up to combat this growing health concern in San Ramon.
"This is a huge issue for us," said Deborah Bass, public affairs manager for vector control. While vector control, the special district agency that protects humans from harmful and irritating insects and animals, has always treated ponds and streams for insects, neglected pools are a new phenomenon.
Much of the problem can be attributed to a rise of foreclosed homes in the area. "We have a real serious problem when people abandon their homes and leave pools unattended," said San Ramon's Chief Building Official and Code Enforcement Officer Reggie Meigs.
In years past, vector control hired three seasonal employees who worked from February to November as part of a "pool crew" monitoring the pools. But because of budget tightening this year, these positions were cut. The agency has had to rely on reserves and reallocate the pool workload to other technicians, Bass said.
"It's harder for us," she said. "But we are doing it."
So far this year, 30 pools in San Ramon have been inspected, and four have been treated for mosquitoes. Vector control inspector Lawrence Brown, who treats mosquitoes in San Ramon, Danville, Alamo, Diablo and Blackhawk, said this number is about the same as last year's.
"But it's June," he said. "It's still early."
The public health concern partially comes from how quickly mosquitoes reproduce: One mosquito egg raft produces around 300 of the bloodsuckers. Extrapolate those numbers and you can see why pools can produce more than 1 million mosquitoes in a 5-mile radius, Bass said.
"I've seen pools that look like they are boiling with mosquitoes," she said.
These mosquitoes are the same breed that carry the sometimes-fatal West Nile virus, Bass said. The hotter the weather gets, the faster the mosquitoes go through their life cycle, and the more likely they are to carry such viruses.
To help identify the mosquito-producing pools, San Ramon code enforcement has sought out foreclosed homes by using www.foreclosedradar.com and driving through neighborhoods looking for signs of empty homes. If a foreclosure is identified, code enforcement will check for a pool and then make a call to vector control for inspection. Neighbors are also encouraged to report these pools or signs of excess mosquitoes to either vector control or code enforcement.
Once a pool is flagged for inspection, vector control will notify the owner, if applicable, take a sample of the pool water, and then begin treating the pool with larvicide.
Often vector control will come back with mosquitofish, which "slurp up the mosquitoes at the surface like spaghetti," Bass said. "It's the perfect marriage." After the pool is treated, vector control places it on a list and continues to monitor it.
Pools are not the only place where mosquitoes are an issue. Birdbaths, spas, flowerpots, toys and vases all collect standing water. Decorative fountains can create a problem, especially in Windemere and Dougherty Valley, Brown said. "A lot of the larger homes have fountains in the front yard and the backyard."
Vector control also monitors stagnant ponds — another mosquito favorite. Brown said San Ramon's new developments Windemere and Dougherty Valley each have large have retention ponds used to collect storm water and rainwater. These are like giant ponds of standing water that must be monitored every two weeks.
Though neglected pools can quickly create a health hazard, Bass assures that if you maintain your pool using chlorine and regular filtration, you should not have any problems.
If you notice standing water or mosquitoes in your neighborhood, she urges San Ramon residents to call and make a report.
"It's very difficult to find these pools in hidden areas," she said. "We don't know it's a problem until people start getting bitten."
At a glance
Contra Costa Mosquito Vector Control online service request form: http://www.ccmvcd.dst.ca.us/request.htm
San Ramon Code Enforcement: 973-2590
Standing water is identified as any water that stands for a minimum of five to seven days. Common sources include trash cans, birdbaths, boats, aquariums, hot tubs, wading pools, swimming pools, spas and Jacuzzis.
How to get rid of standing water:
- Dump and turn over small sources of standing water (garbage cans, bird baths) to prevent the collection of water
- If the problem is a pool, restore the pool's filtration system and apply chemical treatments that will kill algae and bacteria and prevent mosquito breeding
- Drain the pool and make sure it cannot hold water in the future. Be sure to make sure no water is left, as mosquitoes need only a half-inch of water to lay eggs
- Add mosquitofish to the pool
- Call vector control
- Consult a pool maintenance company
Source: California Department of Public Health – Division of Communicable Disease Control