How hard is it to reuse bath water? I’m devoted to the environment, but I’m not sure I want to haul buckets of bath water every night after a relaxing time in the tub.
Gently used household wastewater is called grey water. Reusing grey water from the bath saves a home tens of thousands of gallons of water a year, as well as hundreds to thousands of dollars. Some grey water systems automatically divert bath water to the garden or laundry.
Curious about how to send a huge hug to the earth by recycling your bath water? Here are some of the latest options available, none of which is very expensive, especially when you consider that you’ll save oodles on your water bill.
Reuse Bath Water to Save Money
By recycling bath water, you are essentially saving on your water bill. If you consistently reuse bath water, in the course of a year, you can save hundreds to thousands of dollars on your water bill.
Reusing bath water can also dramatically shrink your environmental footprint. When water from your bath goes down the drain, it usually ends up in a sewer system that flows into rivers or streams. From there, it can pollute the local water system.
While legal to install a grey water recycling system in many states, be sure to check out the laws where you live before investing time and money. According to the Garden Myths blog:
As grey water stands, the bacteria will start to multiply making a potential disease issue worse. Many gray water regulations require you to use the gray water within 24 hours, if it is not treated.
So if you want to pursue using grey water from your bath, how difficult is it? And how much does it cost? Let’s explore these questions.
Low-Tech Methods to Recycle Grey Water from the Bathtub
Some people keep a bucket next to the bathtub. When a bath is finished, they use the water to fill the toilet over the course of the week. Or some hardy souls lug the bucket to the garden. I use the bucket method on occasion. It makes me feel great to water the plants or wash the car with my leftover bathwater.
I especially recommend encouraging children to reuse their bathwater. (See the video above for ideas.) It helps them feel empowered that although they are small, they can do big things to help the earth.
But if you’re looking for something more automatic, you’ve got lots of options.
Pump to Garden Grey Water Systems
Use a pond pump like this one and attach a garden hose or drip system tube After the bath, simply immerse the pump in your tub water placing the hose out the window. Many will empty 30 gallons—a typical bath—in one minute. To keep your garden healthy, don’t always pump grey water to the same place in your yard. And you might want to let the bathwater cool down before putting it onto your plants.
That looks easy enough! But what if you don’t want the hassle? You’re too busy to brush your teeth let alone try the pump-to-garden system. What are more automated options for getting bathwater to the yard?
More Sophisticated Systems for Reusing Bath Water
An organization out of California called Greywater Action has a super-helpful website. Greywater Action provides educational workshops and advice about installing water recycling systems. These systems can restructure your pipes to divert water your garden after you bathe.
Reuse Bath Water with a Gravity-Based Grey Water System
This system involves installing a diverter valve in your pipeline that will funnel grey water from the bathtub into multiple irrigation pipes that lead to your garden. The water flows downhill through the pipes. However, if your garden is located uphill from your home, you won’t be able to use this system.
Reuse Bath Water with a Pump Grey Water System
This will be more expensive to install than a gravity-based grey water system. While you will still place a diverter valve on the drain water, you’ll also need an air pump to redirect the flow since gravity is not on your side.
To DIY the installation of these systems, consult Greywater Action for details. And be sure to check out this example of one Branched Drain System. Keep in mind, it can be difficult to locate the correct pipes if they are buried deep in the walls. Expect to pay $150-$300 for parts. If you want to pay for installation, rates probably start at $1,000.
Also, an important note: To avoid clogged pipes, use pipes that are 1.5 to 2 inches in diameter, and don’t use pipes with U-bends.
High-Tech Grey Water System
The most sophisticated systems involve installing a separate grey water tank. This system filters the water that comes into the tank to get rid of lint, hair and other impurities. It will save a family of four up to 40,000 gallons of water a year.
One company that sells grey water recycling tanks is called the Water Wise Group. It’s a wholesale distributor of greywater systems. Headquartered in Templeton, California, the Water Wise Group ships around the country. Owner Remy Sabiani told me:
Our systems can recycle greywater coming from the bathtub. The main benefit is to reuse the water to water your plants, trees, and flowers. You pay for the water once, and you use it twice!
Remy told me that most clients use the Aqua2use GWDD. Pricing is $699 per unit. He recommends working with a plumber to set up and connect the system, which will usually take 2-3 hours. According to the Water Wise Group, by using this system, the average family of four can save up to 40,000 gallons of water a year!
4 Ways to Use Grey Water from the Tub
There are many ways to use grey water, depending on your collection method. If you’re automatically distributing water to the garden then that’s one thing. But if you’re using a more manual ways to collect grey water, then try using it to:
1. Bathe Pets with Recycled Bath Water
Once your sweaty kids have finished their baths, why not reuse the water for your pets? I doubt Fido will notice or care that the water has already been used. And he’s been smelling a bit lately, right?
2. Wash Your Car with Water from the Tub
Take a few buckets out to the driveway and dump them on your car. You’ll not only save the expense of going to the car wash, if you make a habit of this, your car is likely to look pretty spiffy.
3. Pour Used Bath Water into the Toilet Tank
Some people claim to get 30 flushes out of recycling 30 gallons from of a single bath. That could take care of flushing for your whole family for several days. The added benefit? There usually isn’t too far to take the bathwater. And if you get clever you may able to hook up a pump system so there won’t be any manual labor involved. Just be sure to recycle the used tub water directly into the bowl and not into the tank.
4. Water Indoor Plants with Tub Water
Take a bucket or two of bathwater and use it on your plants! Better yet, invite young children to participate. This can be an easy and effective activity to teach them about recycling, and it only takes a few minutes.
Wait just a minute! I hear you say. What about the soap and other debris like hair or shampoo residue that might be in that water. That could kill my plants!
Well, you’ve got a point. So what soaps and shampoos are safe to use for grey water? Let’s investigate.
Shampoos and Soaps to Use in Grey Water
According to Greywater Action, there are a few main rules to follow when using grey water in the environment:
- Send nothing toxic down the drain.
- Do not allow grey water to enter a freshwater source, like a creek, stream, or river, or high groundwater table.
- Use biodegradable products that are salt and boron free.
Laura Allen is a founding member of Greywater Action and the author of The Water Wise Home: How to Conserve, Capture and Reuse Water in Your Home and Landscape. She specifically recommends the following brands for soaps and shampoos: Aubrey Organics (most types), Everyday Shea and Dr. Bronner’s.
For a complete list of ingredients to avoid in shampoos and conditioners, be sure to take a look at the Red List from the Campaign for Safe Cosmetics.
Contaminants in Recycled Bathwater
Grey water usually contains bacteria that washes off our bodies, as well as chemicals from the products we use.
And if you really want to know…and you may want to stop reading here…there will be some fecal matter found in bath and shower water. But research finds that this is actually no problem for your plants. In fact, you might want to think of it as free fertilizer. Really!
A study found no increased health risk from consuming plants watered with tap water vs. grey water. (Some questions remain about using grey water to water root vegetables that will be consumed raw.) And other studies find that your carrots and tomatoes might even shoot up higher than ever when watered with grey water instead of tap water. Go figure!
Baths and the Environment
If you’re thinking about the impact of your bath on the environment, you might want to calculate your own Bath vs. Shower footprint. While you may think you know which is better for the environment, your own personal bath vs. shower result may surprise you.
And since you’re an earth-lover, we can assume you’d love a little nature indoors. Did you know that there are many plants that will thrive in your bathroom and purify the air at the same time. Check out our post on the 23 Best Bathroom Plants. Just imagine how you can water them with your reused bathwater!
Can I reuse hot tub water?
Yes, you can but you need to ensure the chlorine level is zero and that it is legal to do so where you live. Many hot tubs or jacuzzi’s hold 650 gallons, so diverting that water to the yard would be great. Don’t add chlorine to the water for two days prior to draining the hot tub, and then test the chlorine level to ensure it’s at zero. If it’s not, run the hot tub for a few hours and test again.
Can I use grey water after 24 hours?
If you want to use grey water after 24 hours, you should treat it to prevent bacterial growth. Untreated stored grey water can also start to smell due to diminishing oxygenation of the water.