Can I Water my Plants With Hot Tub Water?

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 Can I water my plants with Hot Tub Water?

10 Plants You Can Water With Your Hot Tub Water

Recycle and Reuse

Water is precious, especially during the summer months when many states are concerned with or in a drought.  Yet, draining your spa water every 3-4 months is necessary to keep your spa maintained and in correct sanitation levels.

Drought Land

You can recycle your spa water and add it in your maintenance routine, potentially saving yourself hundreds of dollars per year from usage and possible fines for excessive water usage.

Your hot tub water is in considered to be “gray” water.  This is water that has been used and is no longer in natural condition.  You can reuse this water on your nearby plants, yard or in some cases your garden! First though you’ll want to make sure it’s in safe condition.

Wait, Spa Water Isn’t Dangerous For Plants?

Not necessarily.  With proper precautions, spa water can be used on a variety of plants (See our list of 10  compatible plants below).

Manhole Drain = Not for draining spas!

You should be draining your hot tub away from the obvious choice of the storm drain or sewer. Most municipalities have restrictions against draining your pool or hot tub down either of those.  These restrictions are in place due to the contaminants in the used water that could harm protected and sensitive aquatic life.

Safe Chemical Levels

Here’s a breakdown of the spa chemicals, balance and temperature levels that work best when using hot tub water on plants.

Chlorine – There is a fair amount of chlorine in typical tap water, but the amount in your spa may be too high for direct, immediate contact with your plants.  Thankfully, chlorine dissipates quickly and you can drop these levels through evaporation.

Allow time for the chlorine levels to fall before watering your thirsty plants. If you aren’t draining your spa anytime soon, scoop up a 5-gallon bucket or watering can of hot tub water, then let the container sit overnight before you use it.  When it’s time to drain your hot tub, turn the spa off and do not treat or use it for at least 24 hours. Alternatively, you can run the jets on high with the cover off to reduce chlorine levels.  Test chlorine levels and when it drops below 1.5 ppm, it should be safe for your plants.

Bromine – Using bromine water on plants doesn’t appear to be hazardous to the plants and should be less of a concern than chlorine.  However, you’ll want to test your water to make sure the bromine levels are lower than the acceptable range for regular spa usage of 2.0 – 4.0 ppm before watering the plants.

Salt Systems – For hot tub users that use salt systems for sanitizing, we do not recommend watering your plants with salt water.  These systems actually produce chlorine from the salt water through electrolysis (Read more about hot tub salt systems).  Even with the low salinity concentrations in your hot tub, it can build up over time in the soil.  For this reason, most plants do not appreciate salt water of any kind.  While few grass types can tolerate saltier soils, if possible, it’s better to drain salt spas away from your plants and lawn.

Temperature – The temperature of your water will definitely have a factor on your plants.  If you allow spa water to evaporate the chlorine overnight or longer, chances are the temperature of the water is fine.  If you are concerned, a sound temperature for plants would be anywhere around 68° Fahrenheit (20° Celsius).

Balance pH – pH should be in the neutral zone of 7.2 to 7.4.  Adjust the levels if necessary, to be harmless for plants.  Use pH Decreaser (sodium bisulfate) to lower pH or Alkalinity Up (sodium carbonate) to increase pH levels.  For those concerned with the alkalinity in hot tub water and the safety of the plants, total alkalinity can easily be tested with a standard test strip.

Keep a 5 gallon bucket nearby your plants full of used spa water that has been dechlorinated, tested and stamped with your approval.  This provides easy access for adding to your watering can.

Read a detailed Infographic about Hot Tub Chemistry here.

10 Plants Thirsty For Hot Tub Water

Plant these near your hot tub to add some color, texture and life to your outdoor space.

  1. Rosemary – Herb
    • Rosemary is fragrant and a great addition to your next meal.
  2. Aloe – Plant
    • Aloe plants require very low maintenance.
  3. Deer Grass – Plant
    • Deer grass is drought friendly, requiring very little water.
  4. Oleander – Flower
    • Oleander is a perfect candidate for your spa water.
  5. Ice Blue Star Plant – Flower
    • Ice plants are easy to grow and drought tolerant.
  6. Marigold – Flower
    • Marigolds are a beautiful addition to your landscaping and provide protection from pests.
  7. Texas Ranger – Shrub
    • Texas Ranger shrubs produce beautiful flowers and can be maintained with little water.
  8. Evergreen Euonymus – Shrub
    • Euonymus plants are disease resistant and require low maintenance.
  9. Juniper – Shrub
    • Juniper trees are adaptable and have low maintenance.
  10. Olive – Tree
    • Olive trees are drought tolerant and do not require heavily filtered water.

Aloe | Marigold | Rosemary PlantsThese plants can be found at your local nursery or hardware store. 

Using the list of plants above can bring some new landscaping to your outdoor space and are a perfect match to use your recycled spa water.  Of course this list is not extensive as there are many other plants that may do well with your hot tub water.  The used water should be applied sparingly on other plants to monitor reactions.

Roses, vegetables and fruit trees can be more sensitive to chemically treated water, so we do not recommend using hot tub water in those areas of the garden.

Some plants love and need acid to thrive. Azaleas, rhododendrons, holly and gardenias are a few that prefer a lower pH. Avoid watering these acid loving plants with hot tub water if pH or alkalinity are high.

Draining Your Spa

When fully draining your spa, consider watering your lawn and plants with it next time.  Prior to draining, allow the spa water to cool and chemical levels to lower.  And remember, most municipalities have restrictions against draining your pool or hot tub down the storm drain or sewer.  Please check with your city for draining guidelines.

Learn more about When to Drain Your Spa.

To recap…

You can recycle your hot tub water in your lawn, on your plants and even in your garden.  Preparing the water for disposal is a fairly simple process.

For your question, “Can I water my plants with hot tub water?”  The answer is yes, but first test Chlorine, pH, bromine and salt levels in the spa water prior to watering your plants and lawn.

  • Chlorine levels can evaporate overnight in smaller containers, or in about 2 days without the tub being treated or used.
  • pH should be in the neutral zone of 7.2 – 7.4.
  • Bromine does not appear to be harmful to plants but should also be tested.
  • Spa water that uses salt systems should not be put on plants. Even low levels of salt can cause damage.


How to Use Hot Tub Water to Water Plants –

I Never Liked Chemistry – Taylor Technologies – pamphlet

Do you already water your plants or lawn with your hot tub water? Let us know in the comments below!