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.
Because there is no main drain on most aboveground pools, you will only be able to lower the water to the bottom of the intake or skimmer, using your aboveground pool filter system. To drain an aboveground pools, either a). Use small submersible electric pump and garden hose, or b).
Main drains are not required in an inground swimming pool, however, they are strongly recommended and can be extremely useful in some circumstances. The advantages of main drains are to give you the ability to drain the water from your pool without the use of a sump pump.
Just siphon with the vacuum hose. Attach it to the vacuum head for weight, feed it down slowly to let it fill, cap it with your hand, and quickly haul it out and over and below the water level inside.
* Can i discharge the backwash water onto my lawn, will it harm the grass / plants? The DE doesn't harm the grass or plants, excessive chlorine or saltwater may. Alternatively you could backwash to a sewer outlet or clean-out.
The best way to drain the pool is to empty it directly into the sanitary sewer line outside your home. The process is simple but can be time-consuming, depending on how fast you are able to pump the water.
Re: Blow-up Pool on Lawn
If there's water in the pool I could leave it out for 3-4 days and there would be minimal damage to the grass.
Things that may damage your lawn
You should never put water on your lawn that contains more than 0.1 parts of chlorine per million of water. Too much chlorine will harm your grass and the health of your soil. It also isn't good for the environment and can get into the waterways and affect wildlife.
Submerge the pool pump's intake hose under the water, as close to the center of the swimming pool as possible. Choose a space on your property for the pump's outlet hose to drain. This area should be away from the pool and the ground should be level to avoid flooding. Turn the electric pump on with clean, dry hands.
Household sink or bathtub - Yes, seriously! Run the garden hose between your pool and your sink or tub and start the flow! This will direct the water to the sanitary sewers.
Swimming pool builders often install overflow drains near the rim of the pool that prevent flooding most of the time. If you don't have an overflow drain, or if it is clogged, it is possible for periods of unusually heavy rain to overflow your pool.
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.
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.
Although you normally clean your pool with a manual pool vacuum or a vacuum device often called a "creepy crawler,'' you can clean it with a standard wet/dry shop vac. The disadvantage to this method is it takes a long time because you have to repeatedly empty the water from the shop vac.
When constructing a new swimming pool, if you are going to use a main drain it is required that you use two. This is due to safety regulations to help prevent Main Trap Entrapment. Main drain entrapment occurs when the suction is so great through a single main drain that a person can become stuck on or in the drain.
The main drain for a pool is a suction port that should be located at the deepest point on the pool floor. A main drain is responsible for aiding in the circulation and filtration of the pool water. Having a properly working and dedicated main drain line can also allow you to fully drain your pool if necessary.