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How Do I Recycle Grey Water at Home?

Our household is pretty green, we do our recycling every day and try not to be wasteful. But it got us thinking if we could do more – and recycle our grey water too?

Grey water is wastewater from the laundry, baths, showers, bathroom and kitchen sinks, water barrels and hot tubs. The easiest way to recycle grey water is to use it to water plants or flush the toilet. Black water, which may contain chemicals and human waste, should never be reused around the home.

Let’s explore the topic of grey water recycling in more detail, and discover what it is, how to do it – and why we need to do it in the first place…

How Do You Reuse Greywater at Home?

First, let’s talk about water types. Clear, clean or potable water is water piped into your home from a municipal source, from a well, rainwater, a spring, or water that’s been purified. Black water is any water that may have poop or pee in it, or may have toxic chemicals in it. 

Grey water is defined as the waste water that comes from laundry, baths, showers, bathroom and kitchen sinks, garden water barrels and untreated hot tub water. 

Reusing grey water achieves two things: it lowers the amount of potable water needed in a household and it reduces the amount of waste water entering municipal sewage treatment plants or your household septic systems.

Some water in your home – black water – you never want to reuse. Never. Ever. But some water – grey water – like shower water, washing machine water, and bathroom sink water, really isn’t that dirty and can be reused. The problem is that the black water and the grey water are gathered and routed out of your house through the same pipes. 

To reuse grey water, you’ll have to either redo some of your plumbing or simply capture all that grey water before it disappears down the drain (aka the bucket method).

What Is a Grey Water Recycling System? 

A grey water recycling system gathers the once-used grey water from your house and uses it again. To flush a toilet. Or to water a garden.

How Do You Reclaim Grey Water?

In the world of grey water reuse, there are two types of methods: low tech and high tech. A low-tech solution is as simple as a bucket or tub. A high-tech solution requires some serious DIY or professional plumbing help but results in a permanent system that will last years.

Statistically, around 40 percent of average household water usage (see the link to the EPA article below) is from showers and sinks, so that’s a good place to start. 

To reuse the grey water from bathroom sink drains and shower drains, you can go low-tech and simply catch it before it goes down the drain. 

Unless you have already made the switch to planet-friendly toiletries, you’ll need to change out your toothpaste, mouthwash, shampoo, conditioner, and hand soap. There are several good choices out there.

If you are going high-tech, you’ll have to do some replumbing. First, check with your local plumbing code authorities about your intended use of grey water.

The problem is that shower drains, sink drains and toilet drains are all plumbed together to run into the sewer or septic system. Check out the linked video below to see how they used a three-way valve, an actuator, and a bathroom switch to collect the bathroom grey water, and then how they plumbed it all out to a citrus garden.

Another popular grey water capture system is the washing machine to garden system, aka laundry to landscape, aka L2L. Washing machines use about 17 percent of the household water budget. For the L2L system, the plumbing is simple and the washing machine does all the pumping work. 

Here’s a great video from Epic Homesteading. In the video, they install two grey water capture systems: one from the bathroom to a row of citrus trees and then one from the washing machine to an artichoke garden.

How Can We Purify Waste Water at Home?

This is not a simple DIY project. To purify black water at home – pure enough to drink – you’ll need some professional help, some bucks, and a reverse osmosis machine. 

How Long Can You Store Grey Water?

Only one day. Most experts say to pump or dump your grey water immediately.

Unfiltered grey water does have some bacteria in it and, with heat, may start to smell. The bacteria comes from your showered skin or washed hands. It comes from your brushed teeth or is rinsed off your vegetables.

What Can You Do With Grey Water?

Most households use grey water for watering gardens and for toilet flushing. 

Can You Use Kitchen & Bathroom Waste Water for Gardening?

You should never – ever – use water that may have feces or urine in it. That water is black water and should be disposed of through your sewage line. 

Most experts also say to avoid reusing water that comes from your kitchen, because it contains so many food particles that can decay. They don’t recommend using water that comes from dishwashers or disposals. 

But let’s say you are washing vegetables prior to chopping. Or rinsing a bunch of grapes. Or washing your hands with biodegradable soap. Or you have a pan full of cooled pasta water. Or rice water. Or a big bin of sous vide water. Or water from steaming vegetables.

Can you use that kitchen water? Absolutely! Your perennials will love it.

How Do You Filter Grey Water for a Garden?

If your grey water is piped from your washing machine (an L2L system), you may have typical washing machine detritus – dog hair, human hair, lint, wads of tissues – that ends up in the grey water system. 

Set up a biofiltration system at the end of the grey water pipes. Use a coarse cloth bag, filled with wood chips or compost, and attach it to the end of the hose. Clean out the cloth bag every month or so.

Here’s a Climatebiz article with a step-by-step DIY grey water system.

Can I Use Soapy Laundry Water to Water Plants?

Yes, but make sure you switch to a planet-friendly soap if you haven’t already.

Is Grey Water Harmful to Plants?

It can be. You’ll have to switch to green products. Avoid using grey water with heavy salts, boron, borate, chlorine bleach, gasoline, grease, alcohol, hair dye, medicines, mouthwash or toothpaste. 

What Plants Grow in Grey Water?

Big, established plants love grey water. Trees, particularly fruit trees, will love it. Established perennials, shrubs and vines will love it. Fruit bushes like blueberries and raspberries will thrive.

Recycling rain water at home

Conclusion: How Do I Minimize Household & Garden Water Usage?

Some day, water will cost a buck a gallon. Until then, convince yourself that saving water is saving money, and you’ll realize there are hundreds of ways to conserve.

Inside the home, the average American family uses around 200 gallons of water per day. Of that, around 24 percent is used by toilets, 20 percent by showers, 19 percent by faucets, 17 percent by clothes washers and around 12 percent is wasted by leaks.

So, let’s start with the top water user – the toilet. Old toilets (by definition, those made before 1994) use up to 6 gallons of water per flush. New, low-flow toilets use around 2 gallons or less. So upgrade your toilets.

Then, there’s the amount of flushing. Do you really need to flush after every Number One? To reduce the amount of flushing in your household, consider letting those Number One’s add up, just a little.

Next up, the shower. Consider replacing your old shower heads with low-flow ones. Set a timer and reduce your showering time. 

Next, faucets. Purchase some small plastic tubs that fit into the bottom of your bathroom sink. A tub is a good reminder to keep the water running as little as possible. Turn off the water while you do your 1-minute floss and your 2-minute brush.

Upgrade your dishwasher to an energy-efficient one. And fix all your leaks.

In the garden, consider switching from grass lawns to drought-friendly, native gardens. Go wild. Go with rocks. Save your money on that in-ground sprinkler system and water by hand or set up a micro drip system. 

Here’s the EPA (Environmental Protection Agency) on water usage in the US. Check out the average water use in gallons per day for your state – you’ll be surprised. 

We’re not going to go crazy with all this in our household – but as a ‘green’ family we will make some changes to recycle or reuse some of our grey water. Every little helps when it comes to being more environmentally friendly. 🙂

Mark H.

Homeowner and property investor Mark H. aspires to bring you the very best outdoor living content, based on his years of experience managing outside spaces. Read more >