Water conservation is a hot topic in Northern California so naturally, many of our potential customers ask us about how much water they use. Let’s walk through how amazingly efficient hot tubs are, especially when you compare them to other common household, water-using items.

How Much Water Do Hot Tubs Use?

A hot tub is usually between 250 and 450 gallons. In our example, we’ll use a 375 gallon hot tub model that comfortably seats 4-6 people. Let’s say your family of four enjoys soaking in the hot tub once a day 4 days a week. That means your 375 gallons is enjoyed 16 times per week and 64 times per month. It’s recommended you drain and refill every 3-6 months depending on usage and maintenance. Let’s say you use the same water for 4 months before you drain it. That’s 64 uses per month times 4 months giving 256 relaxation experiences per 375 gallons of water. And then when you drain the tub, you can connect a hose to the drain and water the landscaping with the tub water. 

If you have a saltwater hot tub like I do and if you use it twice daily, you could extend the life of the hot tub water to a full year between drains and fills. Let’s do the math and count 4 people using the tub once every day. That’s 4 people times 365 days giving you 1,460 relaxing soaks using only 375 gallons of water. That is about a ¼ gallon per person’s soak. 

Watering Your Lawn

Pop up Sprinkler heads watering your lawn use about 3 gallons per minute. Most lawns have 4 to 6 sprinkler heads watering at the same time and are often on a timer running 30 minutes or longer.

How much lawn area are you watering?

If you have 4 sprinkler heads watering your lawn three nights per week for 30 minutes, that calculates to 3 gallons per minute x 30 minutes x 4 sprinklers x 3 days per week = 1,080 gallons per week to water your lawn. 

That’s 4,320 gallons per month and 51,840 gallons per year to water your lawn. 

So, how many times per year could you fill your 375-gallon hot tub with that lawn sprinkler system water?

That would allow for 138 fills of your hot tub each year. Good thing your hot tub only needs to be drained and refilled 1-4 times annually or 1,500 gallons (if you fill 4 times per year). 

And the better news is each time you drain your hot tub, you can safely reuse the hot tub water to irrigate the lawn or other landscaping. 

Irrigation Drip System

How much landscaping do you have on a drip system?

Drip irrigation is a low-pressure, low-volume lawn and garden watering system that delivers water to home landscapes using a drip. A drip irrigation system keeps roots moist, but not soaked, all while using less water than traditional irrigation techniques.

Drip irrigation uses 1/2 to 1 gallon per hour per dripper and many will have 30-50 or more drippers on for 30-60 minutes several times per week. 

So let’s look at your drip irrigation system. Let’s say you have 30 drippers that each water 1 gallon per hour and you run the system four days per week for an hour. That’s 1 gallon per hour x 1 hour x 30 drippers x 4 days per week = 120 gallons per week to water 30 landscape plants. 

That’s 480 gallons per month, which is more water than your hot tub needs to fill it. 480 x 12 months is 5,760 gallons per year. And this is for a rather small landscape area with only 30 drippers. 

You could fill your 375-gallon spa almost 16 times per year with the water used to irrigate with these 30 drippers. 

It’s amazing when you start to think about how we use water and how little water a hot tub uses.

Your Daily Shower

How many people live in your household? Do you all shower each day? How long is the average shower? Would you say it’s maybe five minutes per person per shower? Safe to say there are four people In the house or four showers per day?

A standard 2.5 gpm shower head uses 25 gallons for a 10-minute shower versus a low-flow 1.8 gpm shower head that uses 18 gallons of water for a 10 minute shower.

Let’s say you have replaced all your shower heads with low flow heads because you are water wise and conscientious. Note also that these low flow shower heads tend to require longer showers to fully rinse shampoos and conditioners because the water pressure feels lower. Hmmmm.

So let’s say your household takes 4 showers per day x five minutes each shower x 1.8gpm x 7 days per week = 252 gallons per week down the shower drain. That’s 1,008 gallons per month down the drain. 12,096 gallons per year down the shower drain. And that’s saying you have a very low flow shower head and take minimal short timed 5 minute showers. 

How many times could you fill a 375 gallon hot tub with the water that went down the low flow shower each year? It’s about 32 times you could fill that spa. And your hot tub only needs to be drained and filled every three to four months. 

Hot tubs are amazing!

Flushing the Toilet

And we haven’t started on how much water gets used in flushing the toilet, washing dishes and washing clothes, among other daily water uses.

If you have an older home, it is likely you still have 3.5 gallon per flush toilets. That’s a lot of water being used. The current federal standard is now 1.6 gallons of water per flush. So let’s say you are a responsible homeowner and you have already replaced all your old toilets. It is said that the average person flushes the toilet 5 times per day. 

So, let’s say you have a household of 4 people each flushing a toilet 5 times per day using 1.6 gallons per flush. That is 32 gallons per day or 224 gallons per week flushed down the toilet. That calculates out to 896 gallons per month and 10,752 gallons per year flushed down the toilet.

You could fill your 375 gallon hot tub more than 28 times with that annual toilet water. 

Hot tubs use very little water!

Using Your Dishwasher

Dish washing in the average home uses quite a lot of water.

The average conventional dishwasher uses about 10 gallons per load. Older dishwashers use closer to 15 gallons per load. Dishwashing by hand can use up to 27 gallons of water per load compared to a dishwasher load. Newer water saver dishwashers can use less than 5 gallons per load.

So let’s say your household of 4 people washes one load of dishes after dinner each night. You are responsible and have a good conventional dishwasher that uses about 10 gallons of water per load. That’s 70 gallons of water used per week and 280 gallons per month, which is 3,360 gallons of water per year. We didn’t count any kitchen sink water used to rinse any dishes or to wash pots and pans or to wash your fruits and vegetables or your hands or water used to clean your sink or counters, etc. We only counted the energy efficient dishwasher water use in this exercise. 

You could fill your 375 gallon hot tub almost 9 times with that dish water. If we counted all the other kitchen sink water, we could probably double that amount of water use and fill the tub another 9 times in a year.

Wrapping It All Up

If water conservation is keeping you from purchasing a hot tub, you now know that all your hot tub water is 100% recyclable by using it for lawn irrigation when it’s time to drain it. When you own a hot tub and use it daily, you use the same water over and over again. Hot tubs really are amazing!

Using your hot tub regularly provides you with so many health and wellness benefits. The value of daily soaking in your 375 gallons of hot water is so much more than watering that green lawn. Visit our Hot Tub Learning Center to find out more about the benefits of using a hot tub.