If you own a salt water pool and need to drain water after a heavy rain storm or during winter closing, you obviously need somewhere to pump the water to. If you have a sand or D.E. filter that requires back washing, you’ll need to drain water several or more times each season so it’s something pool owners will need to do from time to time.
The question is…Can you empty water from a salt water pool on your lawn or will it kill your grass? Maybe you need to drain water to a more suitable location given your property layout and design? You might even need to consider local laws, which we’ll discuss below.
Occasionally pumping pool salt water on your lawn generally won’t harm most grasses because the salt content is relatively low, in the range of 2700 to 3400 parts per million. It’s important to remember that some grasses, plants and vegetation are salt-sensitive and pools contain other chemicals that may cause damage.
Your best bet is to bypass your lawn and drain water directly into the local sewage system but another question needs to be asked first: Do you live in an area that even allows draining salt water pools or is using the public sewers prohibited?
Let’s take a closer look at this subject and the related questions regarding emptying salt water on your lawn when needed.
Does salt water damage your lawn?
A salt water pool has a relatively low level of salt content assuming it is maintained within the proper range of 2700 ppm – 3400 ppm. PPM means parts per million. At this level, the salt content is so low, the human palate can’t even taste it, not that I recommend sipping your pool water. In that regard, the salt water from your pool shouldn’t harm your grass due to the low salt level.
Of course, when you dump salt water on your lawn or other vegetation, you’re also dumping other chemicals in the water on your lawn including:
- Chlorine (definitely)
- Cyanuric acid aka stabilizer (definitely)
- Metals (likely)
- Filter cleaner (possibly)
- Algaecide (possibly)
Obviously some of the chemicals are definitely in the pool water such as chlorine and stabilizer but others may or may not be, depending on what you have added. Just worth thinking about in case you have any nearby plants, trees or garden that may not appreciate a large amount of chemically-treated water being dumped on them.
Does salt water kill other vegetation?
Some plants and trees are salt-sensitive. Examples of salt-sensitive vegetation that may be damaged or killed by salt water exposure include:
- Certain grasses i.e. Kentucky bluegrass, Axonopus compressus, Chrysopogon aciculatus, Oplismenus burmanni and Thysanolaena latifolia
- Citrus plants
- Hibiscus
- Onions
- Peas
- Carrots
- Okra
- Strawberries
- Garlic
- Leek
- Chives
- Celery
While some of these plants might not be found in an average backyard, you will see that several common garden variety crops are salt-sensitive and could be negatively impacted by exposure to salt water.
Why do you need to drain salt water from a pool?
The main reasons you’ll drain salt water from your pool at any given time are as follows:
- Excess rain: Heavy rain in the swimming season can cause the water level to become too high. Heavy summer rains can quickly raise the water level above the side skimmer necessitating draining some water quickly.
- Back washing: Filter back washing is required if you use a sand filter or D.E. filter. This is the process of washing the filter and ridding it of all the contaminants it has filtered out of the pool. Filters like these might need to be back washed several times per swimming season and each incidence likely involves removing hundreds of gallons of water from the pool each time to properly rinse the filter medium.
- Water chemistry: To correct some water chemistry problems, the recommended solution may be to drain water from the pool and replace it with fresh water i.e. when you have high levels of stabilizer or Total Dissolved Solids. Sometimes it’s best to drain an amount of pool water and then replace it with fresh water to fix the imbalance.
- Pool closing: Closing your pool in the autumn when preparing the pool for winterization will require removing water from the pool if you live in a cold winter environment with freezing temperatures. This involves draining several thousands gallons (likely) to drop the water level below the water returns to drain the pipes of all water, capping the returns and preparing the pool for a cold, frigid winter.
- Repairs: You might need to completely drain the pool for a specific reason i.e. for repairs, to replace the pool liner, to paint the surface if applicable, etc. On rare occasions, the entire pool might need to be drained of all water and this clearly involves removing a significant amount of water.
In each case, you need a method to pump out the water and drain it somewhere that is safe and legal.
Where else can you drain water from your pool?
Depending on the layout of your pool and backyard relative to the front of your property, it might be challenging to drain your pool without dumping water on your grass unless you have a long enough hose and access to the sewage system because ultimately, that’s where it’s going.
Of course if you’re trying to avoid touching your lawn or garden with any pool water whatsoever, you need a long enough hose to extend out far enough to drain the water so that it completely avoids your grass or other living vegetation, while still being able to avoid inconveniencing your neighbors and reaching the sewage system.
That’s assuming you’re allowed to access the sewage system and you follow laws or rules regarding the condition of the water at the time of draining. Click here for an example of salt water pool drainage laws in Phoenix, Arizona and click here for a Canadian example in the province of Ontario. You’ll see that rules vary considerably between the two.
Some municipalities prohibit or restrict pumping out pool water into public sewage systems, others require a permit and others still may have specific conditions to allow drainage i.e. only non-chlorinated water can be pumped out (you have to wait for chlorine levels to drop to 0 first), the water can’t have visible algae, etc.
What if your local municipality doesn’t allow draining pool water into the sewer system?
In some cases, you might need to hire a licensed water hauler to remove pool water in a vehicle. As the links above show, some local governments limit or even prohibit dumping pool water in the sewage system, storm drains, catch basins or other aspects of your local sewage system.
You can also see limitations or regulations regarding when you can pump water into the sewage system i.e. not after heavy rains when grounds and sewage systems may not be able to absorb extra water. You might also require a permit to drain pool water.
Check with your local municipality to confirm what is required because it can differ from one region to the next.
How can you drain water from your salt water pool without a pump?
You can pump water from your pool quickly with use of your pool pump especially if you have a filter that has a back wash feature. In this case, you’re probably well-experienced with draining water from your pool during filter washing i.e. back washing your filter several times per year.
But if you’re like me, you have a cartridge filter or other style that doesn’t involve back washing and have no method of hooking a hose up to the pump to quickly remove water.
You can purchase or otherwise use a pump that can be placed in the pool to remove water. Short of that you can create a siphon to remove water albeit slower than with a pump.
The easiest way is to use your pool hose to create a siphon to remove water. Here’s how:
- Lay your hose out from the edge of the pool near a water return and run the other end of the hose out of your yard as far as you can to where you want the water to drain from i.e. on your driveway, on the curb of the road, etc.
- With the pump running, hold the end of the hose closest to the pool up against the water return to fill the hose with water.
- When the hose is completely filled with water and begins to drain out on the road, the siphon has started and you can leave the one end of the hose in the water. Water should continue to drain out. You might need to pin the hose down with something heavy to keep it submerged. You might also need a friend to let you know when the water is draining from the other end of the hose if you can’t see it yourself.
Once the desired amount of water has been removed, you take the hose out of the pool to stop the siphoning.
Can water softener salt be used in your salt water pool?
You can use water softener salt in your salt water pool but double check with the manufacturers of your salt chlorinator and salt cell to be safe.
I’ve only used water softener (white pellet) salt for my Hayward salt chlorination system the entire time I’ve had my pool. In fact my pool company has a skid of the same brand of water softener salt in their store that they sell for this purpose.
I’ve written an article on How To Add Salt To Your Pool as well as a Should I Add Salt To My Pool In Winter that helps you learn more about the issue of salt and how it pertains to your pool.
And one of the most popular pages on this website is called Can I Add Salt To My Pool Without A Saltwater System which explains how salt works and what equipment is required in your salt water pool.
Final tips to properly drain your pool
- Before draining water from your pool into the public sewage system, ensure that there are no limitations or regulations against doing so.
- Try to direct water drainage as far away from your house and your neighbour’s houses as you can to avoid the possibility of basement flooding.
- Try to avoid draining large amounts of water immediately after heavy rainfall as the ground is already well saturated with water.
- Avoid draining your vinyl pool on a very hot day if possible since direct sun can help to dry out and damage the vinyl liner.
I’ve written a related article called Can You Fill A Salt Water Pool With Softened Water that might also interest you.
