An aerial view of a greywater discharge facility

What happens to your greywater after you’ve used it in the shower or the sink? Do you know where it goes and what happens to it next? Is there a way to keep this water safe so you can use it for other purposes?

This article will discuss where greywater discharges and how to keep it safe for reuse. Reusing such water can help you reduce your household water bills. So keep reading for all there is to know about this subject!

Where Does Greywater Discharge Go?

Greywater discharges into municipal wastewater treatment facilities or greywater systems. If you have a home greywater system, your household used water discharges into it for reuse in irrigation or toilets. Otherwise, the greywater discharges to municipal wastewater treatment facilities for treatment.

Greywater accounts for 60-70% of household wastewater. This figure means each family member generates approximately 35 gallons (132.49 liters) of greywater daily. Since such high levels of greywater are being generated daily, it’s essential to reuse or treat it before it’s discharged.

It’s worth noting that only water from sinks, showers, and laundry machines can be reused as greywater. Water discharged from toilets, dishwashers, and kitchen sinks with garbage disposals is categorized as black and not greywater.

There are two places where greywater discharge goes:

  • A home greywater system
  • Municipal wastewater treatment facilities

Municipal Wastewater Treatment Facilities

If you don’t have a home greywater system, your household greywater discharges into municipal wastewater treatment facilities. These facilities treat wastewater from households, industries, and stormwater runoffs before reusing or releasing it into local water bodies.

The treatment process includes screening for debris, settling solids, and removing pollutants in the water through biological processes or chemical treatments. The treated wastewater is then discharged or reused.

Ariel view of a various pools in a blackwater treatment facility

However, these facilities are not equipped to treat all pollutants in greywater. Therefore, some contaminants may still be present in the discharged water, posing a risk to local water bodies and wildlife.

That’s why it’s important to use environmentally friendly cleaning products and avoid dumping hazardous materials down the drain. This precaution will help reduce the strain on municipal wastewater treatment facilities and keep the waterways safe for all living creatures.

Home Greywater System

If you have a home greywater system, your household greywater discharges into it for reuse.

A home greywater system is the best way to keep household greywater safe for reuse. It’s a system that collects and filters the water for reuse, typically in irrigation or flushing toilets. These systems can save you money on household water bills and reduce the strain on local water bodies by reducing wastewater discharge.

Installing a home greywater system can be costly. However, there are two types of home greywater systems, and you can opt for the one you better afford. 

These systems include:

  • Diversion devices
  • Greywater treatment system

Diversion Devices

Diversion devices direct greywater straight into the garden or toilet without treating it. This apparatus is the cheapest route as it doesn’t involve expensive setups or equipment. Therefore, it’s your go-to option if you’re on a tight budget.

A pipe from a greywater system that recycles water from an air conditioner dripping water into a bowl outside a home

The system is made up of the following devices:

  • Divert valves – help direct the water into the garden or toilet.
  • Surge tank – this helps distribute the diverted water evenly to prevent plant damage.
  • Irrigation system – distributes greywater into the garden, lawn, or toilet.
  • Filters – these trap debris from the water to avert clogging the irrigation system or toilet.
  • Pump – you need a pump to get the water to the desired point if the system can’t use gravity.
  • Hose – it diverts the water to the farm for irrigation.

The diversion devices, equipment, and installation cost between $1,000 and $2,000 depending on the system’s complexity and the distance the greywater travels.

Greywater Treatment Systems

A greywater discharge treatment system treats and filters greywater to different purity levels before it’s reused, typically in toilets and irrigation. However, this option is more expensive as it requires equipment such as sand filters and ultraviolet light treatment.

A pump-fed greywater system installed outside a home next to the building's exterior

Greywater treatment systems are complex in their operations. The water goes through filtration, pathogen and chemical removal, and disinfection. These processes ensure that the water is safe for reuse for extensive activities.

The cost of greywater treatment systems equipment and installation ranges from $5,000 to more than $10,000, depending on the desired purity level.

A home greywater system can help you recycle more than 2,600 gallons (9,842.07 liters) of water annually. As a result, they are an excellent way to reduce your household water bills and lessen the strain on local water bodies.

Benefits of Home Greywater Systems

Greywater accounts for the highest amount of water discharged from households. You can use it for irrigation and flushing toilets since it’s not potable. 

Therefore, installing a home greywater system is beneficial in the following ways:

  • Reduced water bills – devising home mechanisms to conserve and reuse water will reduce your monthly bills. A greywater system is one such mechanism since it helps you save on water bills by recycling household water.
  • Reduced strain on local water bodies – by reusing greywater, there’s less demand for fresh water from local rivers, lakes, and groundwater which helps preserve these water sources for future generations.
  • Environmental sustainability – reusing greywater reduces the bulk of wastewater to treatment facilities. Thus, it helps prevent pollutants from entering and harming local water bodies. This precaution helps preserve the environment and sustain the wildlife that depends on the water simultaneously. 
  • Increased local food production – channeling the treated greywater to farms helps improve plant growth and crop yields. This application promotes self-sustainability within communities while reducing the carbon footprint of importing food from faraway places.

Although the initial installation cost for a home greywater discharge system may seem high, the long-term benefits outweigh the cost.

So, why not join the movement and start conserving used water today?


As you can see, greywater discharge doesn’t just disappear into thin air. Instead, it goes to different places like your home greywater system, municipal wastewater treatment facilities, or directly into local water bodies.

A home greywater system is necessary if you want to reuse greywater and conserve water.

For sustainable living, take laudable action to keep greywater discharge safe for the environment and future generations. Let’s all do our part in preserving this precious resource.


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