Will Hot Tub Water Kill Grass?

Hot tub owners know it takes a lot of energy and water to keep these wonderful relaxation machines running well. When it comes time to change the water, which most experts recommend be done 3 to 4 times a year for best results, dumping it down the drain and into the sewer can seem like a huge waste of water.

Some clever yard owners try to reduce the amount of tap water they use and direct the hot tub water with a garden hose to be used a second time. 

While supplementing the city water supply with your hot tub water might seem like a good idea, there can be dangerous chemicals and high levels of chlorine. Much like a swimming pool, chlorinated water is used to kill microorganisms that can cause sickness and bacterial infections. The high chlorine level in hot tub water may keep you safe from pathogens, but it can also be harmful if dumped incorrectly.

Read on to see what happens when you dump hot tub water into your grass.

Can Hot Tub Water Hurt My Lawn?

The chlorinated water and heavy water flow of a dumped hot tub will harm your lawn and can lead to expensive turf repairs down the line. While letting water chemicals spill onto your turf is always a bad idea, there are ways to safely dispose of pools of water. Using a hose spigot to reduce the rate of water flow and letting the chlorine levels drop are ways to make dirty water safe. 

The main chemical you will find in every bit of spa water is chlorine. Water with chlorine can help keep freshwater safe from disease-causing bacteria and parasites but will also dry out plants and kills them. Pools of water with a concentration greater than 2ppm will burn a lawn making it yellow, sickly, and weak.

Too much chlorine dripping from a submersible drain pump or incorrect pumping methods can lead to dead grass, especially in a dry climate where plants already lack stable water quality in sufficient amounts. 

To keep water quality safe, bromine is also added to community water. A high bromine level will hurt your lawn and any other plants in your yard if it is incorrectly dumped. From time to time, the chemicals in spa water may spill out and enter your soil. If the bromine level gets too high in the soil in your yard, it can have negative effects.

The damage water with bromine in it can do is great, especially to trees who absorb the chemical through the roots and build it up in the tissue. Eventually, cell walls are compromised, and the plants will die. 

Saltwater is never good for plants, and some spa treatments have high salt levels to establish proper hygiene levels. If a large amount of salt in the gallons of spa water that will be dumped isn’t enough to harm your turf, the hot temperatures and high heat will do the trick.

When all the water in a 650-gallon hot tub comes pouring out on your turf, it will cause serious soil problems. Expect erosion and waterlogging to be the least of the issues you will face if the water spills or the submersible pump ruptures.

Hot Tubs and Grass

There are lots of elements of a hot tub that can prove unfortunate for the grass that gets hit by it. From the water inside to the lid and shadow, everything about a hot tub can create a brown spot or two on your turf. The process to keep your lawn clean and enjoy a hot tub in the summer is achievable, but you need to plan out how and where you will install your hot tub.

Knowing which aspects of a spa’s drained water can harm your lawn can help you take the necessary steps to relax and keep your lawn green. There are alternatives to water with chlorine that still improve water quality, and there are safe ways to attach a drain spigot to move tons of pool water safely. Below are the tragic results of dumping untreated spa water onto your grass. 

ShadeHot Tub PositioningWeak and Yellow Grass
HeatHot Water Pouring OutBurnt and Withered Turf
Extra TrafficStepping in and out of the Hot TubTrampled and Discolored Grass
Water Splashes and DripsPeople Moving inside the TubChemical Burned Patches in the Grass
Accessories Left on the TurfLids and Tub Tubing Left on TurfCrushed Grass Blades and Discoloration Where Light Was Restricted


While not an issue with a drain spigot or trying to move tons of pool water, it can still create an issue when you install your new hot tub. Some turf grasses have virtually no tolerance for shade, and your tub may be creating a new spot that needs more light. If you are blocking the sun on your lawn and it is resulting in weak growth and weed infestation, you may need to take some action.

Adding a shade-tolerant type of grass or starting the process of replacing that area with mulch or landscape rocks can help sort this hot tub issue out. 


Hot water can burn grass blades and even damage the roots. A few drops falling may not ruin your lawn but pouring out the entire contents of a hot spa tub will. Make sure that the fresh water in your hot tub is cool if you will be using it as lawn water. A hot batch of water should never be poured on your lawn, as resodding or resowing the entire affected area is unavoidable. 

Extra Traffic

As groups of people move around the hot tub to get in and out or to bring drinks or snacks, the surrounding turf may get damaged. Ideally, the hot tub will be on a deck or some other raised structure to protect the grass. If not, then the chance of damage to the lawn around the tub will increase. If the grass becomes brown and patchy, consider replacing it with fake turf or another inorganic ground cover.

Water Splashes and Drips 

Sometimes movement in a hot tub can fling water around the yard, and these leftover water droplets may contain chemicals that will burn the turf. While this may lead to some brown spots, this type of turf damage is likely to cause serious problems. If you notice a lot of damaged grass after a particularly active hot tub session, then you can spray the area with water to dilute any of the harsh chemicals burning the grass. 

Accessories Left on the Turf 

Parts of the hot tub that can be removed, like the lid and panels, can sometimes end up on the ground for several days. When changing a filter or sometimes just by accident, a piece of the tub laying on the lawn can harm the grass. Without sunlight and with the crushing weight of the object, it’s possible that your lawn will start to wither. Simply removing the hot tub part that is on the ground should fix the problem, and the grass should bounce back with no issues. 

How to Dispose of Hot Tube Water Safely

Getting rid of your spa water safely is important, or your lawn and property could suffer some expensive consequences. Most hot tub water will contain chemicals that will harm your turf, and large amounts of water can do other damage to your home and structures. Below are some safe ways to remove hot tub water when you need to. 

Sewer System or Street Drain 

The simplest way to drain your hot tub is to have it connected to the city sewer system or your septic tank. Make sure to check with your city ordinances in case there are special instructions on draining this kind of equipment. All of the parts that lead to the drain should be secured and maintained to avoid ruptures, leaks, and other plumbing issues. 

Drain with a Hose

In some cases, a rural hot tub may be able to be drained with a tub into an area of the yard with no vegetation. While this may take a long time, it is a cheap and easy way to maintain your hot tub. Make sure that the hose is draining in the correct area before releasing the plug. Always check that there are no leaks or punctures that could drip dangerous chemicals onto your turf. Remove the hose when done draining to prevent leaving marks in the grass. 

Submersible Pump 

These pumps will move tons of water very quickly but need to be directed to a safe place for the water to go. Pipes and hosing can help direct the water where it needs to go. A submersible pump is a good solution if you want to use the chemical-free, salt-free, and cooled hot tub water to clean around your home. The pump gives you the power to use the water for even more dirty tasks. 

Wash your Car

Spraying your car with hot tub water and letting it run down the driveway into the storm drain is a good solution that empties your tub and saves water use. There is very little that could be in a hot tub that would harm a car, and the amount of water saved can be staggering. Make sure the water doesn’t get sprayed onto your turf if there is still chlorine in the water. Ensure storm drain disposal is legal for hot tub water in your city. 

Dechlorinating Filter

Using UV light and other filters you can run the water through to make it safe for irrigation use is another use for hot tub water. Once the water has been cleaned of chemicals, it is perfectly fine to be used in lawns and gardens. To ensure your water has no chlorine or bromine, you will need a water tester and a proven method of removing chemicals from water. Once it is clean, you can use it wherever gray water can safely be poured. 

Chemical Free Soak Solutions

If you have managed to create a natural soak solution that doesn’t rely on harsh chemicals or salts to keep the water clean, you may be able to dump it safely on your lawn as soon as it has cooled. Plant materials and ionization products can often sterilize water effectively and can be used in place of toxic chemicals. If you have a tub like this, then you can reuse the water with no fears and no harm to your grass.