Two underground home Greywater System storage tanks side-by-side

You might never think about home water conservation until facing a higher water bill than usual. In that case, you may be confused, not knowing where to start the water conservation process. 

A home greywater system is one way to kick-start your water conservation journey.

In this article, we’ll discuss home greywater systems in detail and also touch on why you should consider this system for your home. 

So let’s get started!

What Is a Home Greywater System? 

A greywater system for homes is a water conservation system that recycles used household water through use in the garden or landscape. The system uses water from laundry, showers, sinks, bathtubs, and dishwashers. However, the exception is black water from toilets and urinaries.

Laundering, showering, and dishwashing are among the household activities that consume the highest amount of water. Unfortunately, most of this water is flushed down the drain and lost forever. This wastage is against the green building requirement for water efficiency and reuse.

A home greywater system comes in to solve this problem. Instead of flushing greywater down the drain, the system collects and filters it for reuse in your garden or landscape.

The system contributes immensely towards green building since it facilitates water efficiency and reuse. A home greywater system is especially essential if you have a landscape that needs regular irrigation. 

According to the United States Geological Survey (USGS), landscape irrigation practices account for almost one-third of household water use. Therefore, using recycled water for irrigation can reduce your water bill considerably.

A homemade harvest rainwater collector in use at an energy-efficient off-grid home

Types of Home Greywater Systems

There are two types of home greywater systems, including:

  • Diversion devices
  • Greywater treatment system

Let’s look at both types in depth.

Diversion Devices

These greywater systems divert water directly from your laundry, bathroom, or dishwasher to the garden or toilet. The system doesn’t treat the water before reuse.

Diversion devices are relatively simple and inexpensive to install. However, they can only handle small amounts of greywater at a time. Moreover, the diverted water, especially from the kitchen sink, might be unsafe for reuse if it contains non-biodegradable components.

The diversion greywater system has the following devices:

  • Hose – you’ll use a simple hose to divert the water to the farm for irrigation.
  • Divert valves – these automatic switches help you set when you want the water diverted to the farm or sewer. The valves make it easier to have only safe water flowing into your garden.
  • Closed-loop system – although not approved in some states, this system directs the water into the toilet instead of the garden.
  • Surge tank – the tank levels out the water flow to the garden for better irrigation and prevents flooding in your garden or house by storing the outflow brunt.
  • Filters – this component is for trapping debris and hair to ensure the irrigation system runs efficiently. The residue can block the irrigation system if left to flow with the water.
  • Pump – you’ll need a pump to get water to the different garden parts if gravity is not on your side.
Diagram of a DIY Greywater System
Courtesy of Climatebiz

The Cost of a Diversion Greywater System

Note that the price of a greywater diversion device depends on its complexity. The cost of a pump, filters, irrigation equipment, surge tank, and pipes add up. This sum makes the system costly based on its complexity.

The system alone will cost you between $750 and $2,500. On the other hand, the installation costs range from $250 to $1,000. 

After installing the system, you need irrigation equipment, which comes at different costs depending on your choice.

Greywater Treatment Systems

Unlike diversion devices, greywater treatment systems treat the water to different purity and hygiene levels before putting it back to use.

The treatment system uses filters and sometimes ultraviolet light to remove harmful pathogens. This process makes the water safe for reuse in toilets and, in some cases, laundry machines and showers.

Treatment systems are more complex to install compared to diversion devices. However, they offer higher greywater reuse since they’re safe for a broader range of uses.

Diagram displaying the various components of a greywater filtration system
Courtesy of National Taiwan University of Science and Technology

Processes the water goes through include:

  • Filtration – this removes solid particles like hair and lint. These particles can block and damage your irrigation system if left in the water.
  • Pathogen and chemical removal – the treatment systems remove harmful bacteria, viruses, and chemicals like detergents and nitrogen. This process may use ultraviolet light or chemicals.
  • Disinfection – the water is disinfected through chlorination to make it safer for human use.

The greywater treatment system is helpful if you have a modest garden to water. You can use the rest of the treated water for other purposes, like flushing the toilet.

The Cost of a Greywater Treatment System

A greywater treatment system is a costly option due to the quality of its services. However, the cost depends on your desired purity level.

A basic system costs approximately $4,000. However, you’ll spend upwards of $10,000 for a system that treats water to Class A level. Class A level water is safer for irrigating crops for human consumption.

You must also consider the installation cost. In most cases, the price will be higher if much plumbing work is needed. One such instance is when your laundry and bathroom pipes are spread around the house.

Reasons To Consider a Home Greywater System

Reasons you should consider installing a greywater system in your home include:

  • A home greywater system can help you reduce household water expenses—the system will allow you to conserve water and, in turn, reduce your water bills. For example, since the cost of 10 gallons (37.85 liters) of water is approximately three cents, you save roughly the same amount for every 10 gallons (37.85 liters) you reuse.
  • It can reduce the strain on municipal wastewater treatment facilities – by diverting greywater for reuse, you reduce the amount of water that goes through municipal wastewater treatment facilities. This reduction helps ease the strain on these facilities and conserves energy for treating and pumping water.
  • Such a system supports sustainable living – home greywater systems support green living by conserving water and reducing pollution. The treated greywater can also help irrigate gardens, promoting local food production.

Overall, greywater systems provide an excellent way to conserve water and support sustainable living. Although the cost may seem high initially, it’s worth the long-term savings and environmental benefits.


Due to the skyrocketing cost of living, conserving water and reducing household expenses is essential. A home greywater system for your home can help you achieve these goals while supporting sustainable living. 

Thus, you should consider investing in a home greywater system to save some bucks and live sustainably.


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