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Swimming and Soaking Can Be Costly

The largest place where water is consumed around your home is in your backyard where the pool and hot tub are located. Since you have already invested a great deal of money purchasing the pool or spa, we don’t suggest you get rid of them. However, there are ways in which you can control how much water is used and lost from the pool or spa.

We get it; you’ve worked hard to save up to have your pool or spa installed. Don’t worry. There’s no need to get rid of them. Here are some ways you can save water and money and still enjoy the use of your outdoor sanctuaries.

  • Use a pool cover. An uncovered pool or spa can lose about half the water in them to evaporation. If you cover them when not in use, you can prevent 90 to 95 percent of the evaporation.
  • Check for leaks on a regular basis. Keep an eye out of damp spots and wet soil around the pool or spa. Any leaks should be repaired quickly to reduce water loss.
  • Reduce the temperature. If you use heaters to warm your pool or spa, reduce the temperature in warmer months. This will prevent losing water to evaporation.
  • Only drain the pool or spa when necessary. Avoid having to completely drain the pool or spa by keeping up on their maintenance. A pool will only need to be drained every 3 to 7 years if properly maintained and a spa every 3 months if you use it on a regular basis.
  • Drain filter backwash from a pool or spa for reuse for lawn watering. You can empty the filter backwash on the lawn and greenery to water your lawn or you can collect it in buckets for use at a later time.
  • Turn off fountains and waterfalls.  A fountain or waterfall may look pretty, but they are a waste of water. Never let them run around the clock and use them for entertaining only.

Your savings will vary depending upon your specific swimming pool and situation, but by implementing a few simple efficiency measures it should be possible to save a substantial amount of energy in your swimming pool.

You don’t need to get rid of your pool or spa to save water. If you are willing to implement some of the steps discussed above, your family can continue to enjoy your pool or spa without wasting water or spending lots of cash.

Drought Action

In a severe drought you may be restricted from adding any water to your swimming pool, backwashing, etc. This may effectively shutdown your pool for the year.

The bad news is the swimming season is over. Consult your pool specialist before removing water from your pool, as some pools require a certain amount of water to maintain structural integrity.

The good news is that you can use the water in your pool to water your plants! Allow the chlorine level in your pool to drop to a level that won’t damage your plants. Use a siphon hose or buckets to distribute water across you landscape. Keep using your pool cover to prevent evaporation.

Pool and Spa Water Use

The amount of water used to fill and maintain a swimming pool throughout the year is affected by a variety of factors including:

  • Size of the pool (surface area and depth)
  • Amount of evaporation (related to local climate)
  • Frequency of backwashing
  • Leakage
  • Frequency and method of pool and pool deck cleaning
  • Splashing
  • Presence and use of a pool cover
  • Temperature of pool water (warmer water evaporates more easily)
  • Presence of a fountain or waterfall
  • pH and chemical content of pool water
  • Individual maintenance habits

Because of the variability of conditions listed above it is difficult to determine how much water a swimming pool will use.

By comparing homes with and without swimming pools and correcting for differences in landscape size its estimated that homes with a swimming pool use about 58 percent more water outdoors than homes without a swimming pool. This research indicates that the addition of a swimming pool results in a substantial increase in water use.

Pool and Spa Wastewater Savings

Unless your pool is purposely drained, most water that you add to it will never become wastewater. In general, most pools seldom require draining except for the occasional cleaning and repair.

However, in areas where the water contains a high concentration of total dissolved solids (TDS) or in colder climates, pools will often be drained on a yearly basis. If you are draining your pool, never drain it directly into a storm sewer or a nearby lake or stream. Pool water contains chemicals, including chlorine, which can be harmful to aquatic ecosystems.

Be sure to follow the proper protocol when draining your pool. flickr/PDQuesnell

When draining your pool, you have two options: use the water to irrigate your landscape or drain the water into a sanitary sewer. If you are unsure of what method is right for you, you may want to consult with a city official or a pool industry professional before proceeding.

To use the water for irrigation, let the pool sit for a few days without adding any chemicals (this allows the chlorine to vaporize). Then you can slowly drain some of the water onto your yard. However, be sure that it does not produce runoff into the streets or storm sewers.

Alternatively, you can drain the water into a sanitary sewer. Below is a step by step method of draining your pool into a sanitary sewer that was developed by the Southern Nevada Water Authority:

  1. Shut off the power to the circulation system at the circuit breaker.
  2. Locate the clean-out port to access the sanitary sewer line. The port is usually located in the ground and close to the home in the front yard—it may be near a water spigot. The port should have a rubber or threaded cap with a square wrench fitting and should be three to four inches in diameter. If you can’t locate the port, contact a plumber. (Caution: Using a clean-out in the wall creates greater potential for water to back up into the house.)
  3. Run a drainage hose from the sewer clean-out port to the pool, and connect it to a submersible pump. Lower the pump into the deepest part of the pool, near the drain. As you begin draining, monitor the water’s flow into the clean-out port to ensure that the water doesn’t back up. If the water begins to back up, stop draining and contact a professional plumber. The maximum recommended discharge rate is 12 gallons per minute. (Note: Any hoses or equipment inserted into the sewer line can become contaminated.)
  4. After draining your pool, refill it as soon as possible. Direct sunlight can damage the plaster in your pool if it’s left exposed. It may take a few days for the fresh water to reach the proper chemical levels, so check the levels every day for a week and add chemicals as needed.
  5. If you’re unsure about draining your pool, or you’d like assistance, contact a professionally-licensed pool service company or plumber. By following these guidelines, you can ensure your drained pool water is properly treated and recycled.

Benefits and Costs

It is estimated that the energy costs to heat the nation’s 5.7 million pools and spas run in the billions of dollars annually. Outdoor pools use high amounts of energy to heat water, which loses heat during the evening and through evaporation. Indoor pools use a lot of energy for systems that remove evaporation-caused humidity.

A pool cover can dramatically reduce energy use by a swimming pool. A pool covered just half the time can save up to 50 percent in annual energy costs.

A basic pool cover with enough material for a 30-foot by 15-foot pool will cost around $80. A storage reel for the cover costs about $160. A high quality insulating pool blanket can cost up to $700 for a 30-foot by 15-foot pool.

Reducing the water temperate just four degrees, from 82 to 78 degrees, can cut your pool’s natural gas costs by as much as 40 percent. If you live in a sunny region you might consider installing a solar heating system for your pool.

Table 1 shows some savings estimates for pool covers. To use this table to estimate costs for you pool, divide your pool’s surface area (sq. ft.) by 1,000 then multiply this number by the heating costs and savings figures for your pool type in the location that most similarly matches your local climate.

For example let’s say you live in Chicago and have an outdoor pool that is 30 x 15 feet. Your pool’s surface area is 450 square feet. Divide 450 by 1000 to get a value of 0.45. From the table you find the annual heating costs for an outdoor pool in Chicago is $1,024. Multiply this by 0.45 to get an estimated annual heating cost of $461.

Table 1: Estimated Swimming Pool Heating Costs and Savings (from the U.S. Department of Energy RSPEC! pool efficiency program)

City Pool Type Annual Heating Costs Pool Cover Savings
Atlanta Indoor
Boston Indoor
Chicago Indoor
Dallas Indoor
Denver Indoor
Kansas City Indoor
Los Angeles Indoor
Miami Indoor
New York Indoor
Philadelphia Indoor
Phoenix Indoor
San Francisco Indoor
Seattle Indoor

*Fuel cost assumption: Gas, $0.50/therm

Tim Caldwell


Friday 15th of April 2022

Do the outdoor pools in Los Angeles and Phoenix cost so much more because they're used year-round?