Graywater Systems for Homes: Complete Guide

Graywater is a precious resource, and currently, it is simply running down your drain. But it is easier than you think to use your gray water to turn your garden into an oasis. So why not get started now? 

One of our methods only requires a bucket and is better than a gym membership.

What is gray water?

Before we dive in and actually look at different types of gray water systems, let’s be clear on what graywater is. And clear is exactly what graywater is not. 

When you turn on the tap, clear water comes out. But after you wash your dishes or your clothes, or even yourself, the water running down the drain is no longer clear. Now it has soap residue or food particles in it. This wastewater is what we call graywater.

Graywater can do more for you than simply run down the drain. As long as you are using the correct soaps, you can divert this water to your lawn or garden. Not only will it reduce your water usage overall, but graywater can actually help your plants grow better. 

It is important not to confuse graywater with black water. Black water is the water that exits your toilet. Black water may contain traces of feces and so must be treated differently. Now, if you are really concerned about water conservation, you can eliminate the need to worry about black water entirely by using one of the best composting toilets. These dry toilets don’t use any water at all. 

So now that we know what gray water is, let’s examine the different types of graywater systems. Then we will move on to some examples of graywater systems you can install for your eco friendly homestead.

Types of Graywater Systems

Like everything else, You can design your gray water system simply or complicated. Which approach is best for your off grid home is going to depend on several factors, like how much work you are prepared to do, your property layout, and ultimately how much money you want to invest in your system.

But just like purchasing a low-flow showerhead to lower your water usage and water bills, building a graywater system can save you money as well. I mean, think about it, you can use all that right now is just going down your drain to water your lawn and garden. As you reduce your water consumption, not only do you save on water bills, but you help save the planet as well.

greywater systems
Photo credit: Flickr

Bucketed

The simplest system you can use to divert gray water to your garden is to use a bucket. While this method won’t work well for all your gray water runoff, it can be an easy way to get started. 

To use the bucket system, you simply collect your gray water into a 5 gallon bucket (or really a bucket of any size). Once the bucket is full you can then use it to water your lawn or garden. Just make sure you are not using it to water edible plants you plan on consuming raw. 

A great example of how you can implement the bucket system is in your shower. I mean, take a minute and think about what really happens in the morning when you take a shower. 

You turn the shower on, but the water starts to come out cold. So you decide you will wait until the water warms up before you get in the shower. Maybe you stand there with your hand under the stream, waiting for the right temperature. Or perhaps you multi-task and brush your teeth while the water heats up.

Either way, gallons of perfectly clean drinking water are just running down your drain!

But imagine if you kept a bucket in your bathroom to collect that water. When you turn on the water to warm up, just put the bucket in your shower. Since the average shower uses 2.1 gallons per minute, you will probably find that bucket gets pretty full pretty quickly (1). When the water is at the right temperature, simply move the bucket out of the way. Later you can bring it to your garden. 

If you have a family of four and each of you averages just 1 minute letting the water heat up, you are saving 8.5 gallons of water a day! Over a week that adds up to a 55 gallon barrel of water you can save- just capturing the water in your shower in a bucket.

But maybe emptying a five gallon bucket of water from your shower into your garden daily isn’t your idea of fun. While it eliminates the need to go to the gym, it gets old pretty quickly (trust me, I’ve done it before). 

So let’s look at other types of systems that are a bit more complicated but also more hands off. 

Gravity Fed 

If carrying buckets isn’t your thing, you can simply let gravity do all the heavy lifting for you by using a gravity fed system. Installing a gravity fed system is going to involve a few more parts than just a bucket, but once you hook it up, it’s pretty hands off.

Right now when water runs down your drain, gravity brings it out of your house through pipes. These pipes go either to a septic tank or a sewer. The key to a gravity fed system is simply diverting where that wastewater goes. Rather than heading to the sewer system, it instead runs to the garden to water your fruit trees. 

The ideal slope for gravity fed drainage is a1/4 inch per foot.

To make a gravity fed system work, you will need to be able to send the water slightly downhill. So be prepared to dig. 

Unfortunately, if your garden is located uphill from your home, a gravity fed system won’t work for you. But you are not without options. A pumped system may work for you.

Pumped Systems

Pumped systems are more complex than either of the other gray water systems we have discussed so far. However, if the area you are looking to irrigate is uphill, a pump system is your best option.

These systems work by first pumping your gray water into a holding tank. The tank allows large amounts of water to be discharged into the system at the same time. The water is then pumped from the tank to your garden using an irrigation system.

While gravity fed systems do not require power, pumped systems do- which is something to consider if you are running an off-grid energy system. And in most of the above systems, your gray water is not filtered, simply applied directly to your garden. However, more complex systems can pass through sand filters to help clean the water.  

Examples of Common Graywater System Designs

grey water garden
Photo credit: Flickr

While you could simply set up a tube that leaves your house and ends in your garden, the “drain out back” system is less than ideal. While it gets your gray water out of your sewer and into the yard, really, it just ends up in one swampy, potentially stinky location. 

However, you can install one or both of the following graywater systems without too much work.

Laundry to Landscape System

The easiest place to start is with your laundry system. Even if you are using the best off-grid washing machine, you are still dumping gallons of gray water every week just from washing clothes (2). 

“The Laundry to Landscape system is the simplest, least expensive, lowest effort way to get the most greywater out on to the home landscape most effectively. Due to its inherent simplicity and low cost, it has been widely adopted, accommodated in building codes, the subject of numerous government rebates, workshops and government training.”

Using this system, you hook up just your washing machine to a tube that leads out to the garden. The system relies on the pump in the washer itself to get the water from inside to out. All you are doing is diverting where the water goes. Because this system uses a pump, you can send water quite a distance from your home and distribute it with the proper tubing. 

You can set up just a laundry to landscape system, but to really get the most out of your gray water, you can combine it with a branched drain system, like the folks in this video did.

Branched Drain Graywater System

If you want to utilize all the water going down the tubes, you should install a branched drain system. Rather than having just a single tube that the water exits your house, you install a series of branching tubes. 

These tubes combined with gravity will help distribute water throughout your garden. As you plan your branched drain system, remember to account for the correct slope. It must remain ¼ inch per foot to get proper drainage in the system.

Final Thoughts

By investing in a graywater system, you can help reduce your water consumption and your water bill. While the bucket method is the cheapest way to get started, looking into a whole house gravity fed system makes the most sense in the long term. But even installing the simple Laundry to Landscape system can help make a dent in your water consumption and the health of your garden.

FAQs

Yes, you should use certain soaps with your graywater system. It is essential to make sure the soap you use does not contain high concentrations of salts or boron, as these can adversely affect your plants and soil.

However, there are many graywater safe products readily available on the market today for your needs, including body soap, dish soap, and laundry soap.

Graywater systems are legal in many jurisdictions, including the state of California. However, before installing a gray water system in your home, you should check what local regulations apply to ensure that your design falls with the codes of your area.

The cost of gray water systems varies depending on their complexities. They can be as inexpensive as simply buying a 5 gallon bucket to place in your shower. However, the more complicated your system, the more it will cost.

Pumped systems and filters will cost more than a DIY gravity fed gray water system.

  1. Save Water and Energy by Showering Better. Retrieved from: https://www.epa.gov/sites/default/files/2017-02/documents/ws-ourwater-shower-better-learning-resource_0.pdf
  2. Laundry to Landscape Greywater System. Retrieved from: https://oasisdesign.net/greywater/laundry/
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