Swimming Pool Tips

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Conservation staff has limited information about swimming pools. For additional information regarding pools please contact a local pool company. The following information has been provided to us by: David Metzger, Pool Covers Inc.; Jim Kany, American Leak Detection; and Don Koss, Marin.

Want to save money, energy and water while properly maintaining your swimming pool? To help you, we've talked to local experts and put together money saving tips on these important topics:
  • Pool covers
  • Leaks
  • Pumps
  • Filter systems
  • Water quality
Pool Covers
  • Using a pool cover regularly reduces evaporation by 90 to 95%.
  • Without a cover, an average pool of 18 feet x 36 feet loses about one inch of water per week in the peak of summer. This can add up to an annual water loss of 7,000 gallons.
  • One of the most important benefits of using a pool cover can be enhanced safety.
  • You can cover a pool without being concerned about gaseous exchange, unless you are using chlorine gas. If you are using chlorine gas, you should let it air.
Pool Leaks
Clues Which May Indicate a Pool Leak
  • Algae or other persistent water quality problems
  • Loose tiles or cracks in the pool deck
  • Cracks and gaps in the bond beam
  • Water-saturated soils in the area around the pool, pool pumps, or plumbing
Checking For the Leak
If you suspect your pool is leaking, there are several reliable ways to check. Try one of these approaches:
  • Use a grease pencil to mark the water level of the pool at the skimmer. Check the mark 24 hours later. Your pool should lose no more than 1/4 inch per day. Otherwise, a leak is indicated.
  • The bucket test: Place a bucket filled with pool water on a pool step, weight it with a rock or brick. Mark the water level on both the inside and the outside of the bucket. The starting point levels should be about the same. Check the mark 24 hours later. If there's a greater drop in the line on the outside of the bucket, a leak in the pool is indicated.
When in doubt call a leak detection company to further assist you in determining if your pool has a leak.

Determining the Location of the Leak
If you determine that your pool is losing water, turn off the filtration system and note where the water stops dropping.
  • If the water stops at the skimmer, the leak is probably in the filtration system. The lines may crack at vulnerable elbows and fittings that are under stress from shifting soils.
  • If the water stops at the light, the leak is probably there.
  • If the water drops below the light, then there may be a leak in the drain at the bottom the pool.
If you suspect you have a leak in the filtration system these clues may help you pinpoint the location:
  • If you see bubbles in the return water when the pool's pump is running, it's likely there's a leak in the suction side of the filtration system.
  • If the pool is losing more water while running the pump, then water is being lost on the return side of the system.
Pumps, Filters & Water Quality
A pump should be able to circulate pool water at least every 24 hours, but every 8 hours is preferred.
Most existing pool pumps are over - sized for the size of the pool and plumbing, which reduces filter effectiveness and causes more wear and tear on plumbing. For the average 1-1/4 inch to 1-1/2 inch plumbing pipes, a pump of only 1/2 horsepower is needed. Many pool owners have bigger pumps, which dramatically increases electrical pumping costs. For example, a 1/2 horsepower pump will cost about $300 per year to run, while a 3/4 horsepower pump will cost $450.


Current cartridge filters are now almost as effective as diatomaceous earth filters, are much easier and safer to maintain, and require very little water for cleaning. Each time you backwash sand and diatomaceous earth filters you use about 500 gallons of water.

Water Quality

Proper chemical balancing can prevent and cure most water clarity problems.
When is it appropriate to dump your pool water? Not as often as you may think. Pools can often go 10 or more years without draining and refilling. Here are some guidelines:
  • When the total dissolved solids (TDS) get too high.
  • Water quality problems often can be solved by draining only a portion of the water.
  • If you have to drain your pool, make sure you take steps to prevent the pool shell from popping out of the ground. Using a hydrostatic valve or drilling holes in the bottom of the pool can prevent this problem.
  • To properly dispose of your pool water, contact your local wastewater treatment plant for instructions before draining your pool. For information about protecting local waterways please contact the Marin County Stormwater Pollution Prevention Program.
Helpful Resource
Discharging Water from Swimming Pools, Spas, and Fountains