What is the Cost To Install a Greywater System?


Published: April 10, 2022 | by Wahaso Water Harvesting Solutions

What is the Cost To Install a Greywater System?

Water is a precious resource that we all must strive to conserve. For businesses, this means looking into water conservation systems. They’re a significant investment to start, but they pay for themselves over time and help safeguard an essential resource. One type of water conservation system is a greywater system. Here’s what you need to know about greywater systems, including what they are, how they work, and how much they cost to install.

What Are the Different Types of Water Used in Buildings?

Two common types of water used in buildings are potable (drinking) and on-site treated non-potable water. The municipal wastewater plant treats potable water to remove impurities and is safe to drink. O-site treated non-potable water is brought to a lower quality standard and is not meant for washing or ingestion. Examples of on-site treated non-potable water include greywater, rainwater, stormwater, and condensate.

What is Greywater?

Greywater is non-potable water from gently used sources such as showers, sinks, and laundry systems. It does not include blackwater from toilets or water that has come into contact with hazardous materials. Unlike rainwater, greywater contains soap, detergent, skin cells, and anything else that might go down a sink or shower drain.

How Does a Greywater System Work?

A greywater system uses a second set of piping to collect and convey greywater from showers, sinks, and laundry machines. The greywater is then filtered, treated, and stored before its reuse. Greywater is commonly used for irrigation, flushing toilets, and cooling tower make-up.


Greywater systems keep the building’s outdoor appearance beautiful and green without wasting valuable drinking water by using greywater for irrigation. While conventional greywater systems do not filter all the contaminants out of the water, the more advanced systems can bring the water to a very high-quality standard. Many manufacturers tout the benefits of excess nutrients in greywater though this is primarily a side-effect of ineffective water cleaning and separation. It’s also safe for fruit and vegetable gardens because it doesn’t contain harmful chemicals and contaminants.

Flushing Toilets

You can also use greywater to flush toilets. This conserves fresh water and reduces the amount of sewage that needs to be treated. You can also add a rainwater collection system to your greywater system to increase the amount of water available for flushing toilets.

Cooling Towers

Commercial buildings often use cooling towers to regulate indoor temperatures. Cooling towers can use millions of gallons a year, so using greywater can significantly reduce the amount of freshwater needed. Because it’s a closed-loop system, the water doesn’t come into contact with people, so there’s no risk of contamination.

Swimming Pool Make-Up

If you have a swimming pool, you can use greywater to top it off and reduce the amount of municipal water needed. This strategy can save apartment complexes, hotels, and other commercial buildings with pools. The fact that harvested greywater can be used in pools provides insight into how clean on-site treated non-potable water is.

There are two types of greywater systems:

1. Decentralized

Each business has its greywater system. A decentralized unit is best for businesses that use a lot of greywater and want to reuse it on site. Laundry services, landscaping companies, and medical facilities can all benefit from decentralized units.

2. Centralized

A single, more extensive system serves multiple buildings, such as an apartment complex, shopping center, or school campus. This can help save money and resources while ensuring the system is designed to meet the variable demand. A Wahaso representative can work with you to assess your needs and recommend the best type of system for your business.

Are There Any Challenges to Installing Greywater Systems?

There are some challenges when installing a greywater system. It’s essential to have the right system for your building and to make sure it is sized correctly. You also need a place to store the greywater and a way to treat it before using it. You can overcome these challenges with the help of a professional who has experience with greywater systems. Another area to navigate is local and state regulations. Some states have laws restricting greywater use, so you must check with your local authorities before installing a system. Our team at Wahaso has over 75 years of combined experience in water recycling and reuse. We can help you overcome the challenges of installing a greywater system and take advantage of its many benefits. We can also help you navigate local regulations and ensure your system is compliant.

How Much Does It Cost To Install a Greywater System?

The cost of a greywater system depends on the size of the system and the type of business. The starting price for a small, decentralized system is around $250,000. More extensive, centralized systems can cost more than $1 million. However, these systems offer a return on investment by reducing water bills and sewage treatment costs. They can also help businesses earn LEED points, leading to tax breaks and other financial incentives.

What Are the Costs of Maintenance and Operation?

The costs of maintaining and operating a properly designed greywater system are a small fraction of the savings received annually. Schedule regular check-ups with a professional to ensure your system is running smoothly.

Overall, a greywater system is a wise investment for businesses that use a lot of water. Greywater systems are also good for the environment, as they reduce the amount of wastewater that needs to be treated. While not every building is well suited to greywater reuse, a significant percentage of buildings being designed and constructed could greatly benefit from this water conservation strategy.

If you’re interested in installing a greywater system, contact Wahaso today. We can help you with an initial feasibility study to determine if this is the right strategy for your project. Once designed, Wahaso provides fully operational systems with commissioning and a comprehensive warranty.


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Our mission at Wahaso is to help municipalities and commercial property owners reduce the impact of their buildings on the environment through innovative and sustainable water practices.