Even with proper and regular pool maintenance, it's often necessary to drain your pool — completely or partially — every 3-5 years. Draining your pool often isn't necessary, especially if you're following a proper and regular maintenance program.
The Danger of Hydrostatic Pressure
If you have a concrete pool, the pressure of the water below can cause the floor to shift and crack. In a vinyl or fiberglass pool, the hydrostatic pressure below can actually lift the floor of the pool, causing severe damage to the floor and the walls.
Pool industry experts recommend you drain your pool and refill it every five to seven years. No two pools are alike, so there is no set number at which you must drain your pool.
Draining or emptying your pool of water can create a number of financial and structural headaches, including: Cracking the pool's shell. Damaging the interior lining or surface. Damaging the pool's coping and surrounding paving or timber work.
Inground pools should only be drained when you need to stabilize your pool's TDS or if a repair to the interior is necessary.
When to Replace the Pool Water
You should replace pool water every five to seven years. As much as possible, you should drain and refill your pool during mild weather. It's to avoid pool damage caused by direct sunlight and heat. Moreover, a pool maintenance company can recommend the ideal time to drain your pool.
Close the pool for winter – but don't drain it.
In winter, the water in your pool is still your friend. Especially when properly winterized, it helps to protect the pool liner, keep it clean and prevent unnecessary damage from debris, harsh weather and other factors.
The big reasons for draining a pool are either that a repair needs to be performed that can't be done with water in it or that you need to stabilize the level of Total Dissolved Solids (TDI). Almost every other problem can be solved without draining.
Empty pools are also susceptible to damage from exposure. Vinyl pools tend to contract when emptied, which can result in damage when they are refilled. Gunite or fiberglass pools can crack, and fiberglass pools may suffer bulging or splitting if drained. It may also void your warranty to drain your fiberglass pool.
Generally, pool water needs to be replaced once every five to seven years. This should be done during mild weather so that your pool surface is not at risk from strong sunlight and heat. Your pool maintenance company can recommend when it is time to drain your pool.
In general, draining this type of pool is the trickiest. Inground pools made of concrete or gunite are susceptible to popping out of the ground if drainage is not done properly. If there has been a surplus of rain recently or your pool is located in a wet area, it is best not to try and drain the pool yourself at all.
If you have a typical rainfall, or even several inches, your pool should be fine, since drains and skimmers are designed to remove the excess water. In most cases, your pool can even handle rain from most tropical depressions and hurricanes.
During normal operation, water flows to the filtering system through two or more main drains at the bottom of the pool and multiple skimmer drains around the top of the pool. The main drains are usually located on the lowest point in the pool, so the entire pool surface slants toward them.
Go to the back of the filter and unscrew the drain plug. Turn the pump back on and let the water run until it reaches the point where you want to drain the water out. Turn the pump back off and put the plug back into the drain plug.
Modern concrete pools can usually stand being drained for as long as needed, but there'll still be a risk of popping if the ground water level is high. Fibreglass pools are less resilient. The floor may come loose and float to the top when refilled, even after a short period.
All you need is a medium-size water or vacuum pump. Unroll the pump's intake hose so that it reaches the center of the pool (or as close to it as possible), and submerge it in the pool. Place the outlet hose so the exiting water doesn't flood the area, but drains off away from the pool.
A 10,000 gallon pool will take about 14 hours to drain, the maximum rate recommended by the City of Phoenix. It will take twice as long to drain if the pool size is doubled or cut in half.
Important: Never completely drain an above ground pool. This can cause your pool to collapse. If your pool is plumbed with detachable, flexible hoses, remove them and store for the winter. Remove all drain plugs from the pump, filter tank, and any other pool equipment.
The average cost to fill in an inground pool is $4,000 to $16,000 for full demolition or $2,000 to $10,000 to fill in with dirt. An above ground pool removal costs $300 to $800, or $2,500 with a deck. The cost to get rid of a swimming pool depends on the size, depth, material, and accessibility.
Except for emergencies (which we will discuss momentarily), home pools typically only need to be drained once every two or three years. Commercial pools, if properly maintained and serviced, should be drained and the water replaced annually.
If you can pump around 30 GPM (gallons per minute), which is also equivalent to 1800 GPH (gallons per hour), it should take you 2.78 hours or 2 hours and 46 minutes to drain your pool using a hose.
Flooding Your Grass Is Not A Good Idea
The problem with draining your pool in the yard, if permitted by your local water regulatory laws, is that it will quickly reach its saturation level and increase the risk of flooding your lawn, drowning the roots of your grass, and attracting mosquitoes.
Pool water should never be drained to the street or the storm drain. Storm drains in the Bay Area typically run into local creeks, rivers and the bays. In most places, it's against the law to drain pools and spas this way because pool water contains chemicals that can endanger or kill wildlife.
Too much rain can raise the water level in your pool to overflowing if you're not careful. If the water in your pool is in danger of overflow, you may need to drain the pool. There are numerous how-to videos online that go over this process.