How To Build A Greywater System

Hey friend! Looking to build your own greywater system? You’ve come to the right place.

In this handy guide, I’ll walk you through everything you need to know to build a simple, effective greywater system right in your own backyard. Reusing water from sinks, showers, washing machines, and more to irrigate your garden is a game-changer when it comes to water conservation and saving money on your utilities. Plus, installing your own system is much more affordable than paying a contractor.

By the end, you’ll be a pro at installing diverters, setting up filters, connecting pipes, and getting a top-notch irrigation system up and running. Let’s dive in!

Planning Your Greywater System

The first step is deciding what exactly you want your system to do. Here are some key considerations:

  • Water sources: Which fixtures do you want to capture water from? Most systems pull from washing machines, showers, and bathroom sinks. Kitchen sinks have a higher level of contaminants, so they’re often avoided.
  • Irrigation needs: How much greywater do you need for irrigating your lawn, garden, trees, etc? This will determine the size of your storage tank.
  • Gravity or pumped: Do you want the greywater to flow via gravity through the system? Or will you need a pump to move the water? Pumped systems require a bit more work but give you more flexibility.
  • Check local codes: Most areas allow simple greywater systems, but some have restrictions. Check with your local utilities department before getting started.

Once you’ve mapped out the basics, it’s time to pick out the right components, like piping, filters, storage tanks, and irrigation methods. Planning it out first makes installation smooth sailing.

Setting Up the Water Collection

The first piece of the puzzle is getting the greywater from its source to the rest of the system. Here’s how:

  • Add a diverter valve on the pipe exiting water sources like washing machines, showers, or bathroom sinks. This lets you split the flow between your home’s plumbing and the greywater system.
  • Use a hole saw to cut an access point in the drain pipe. Pop in a y-shaped diverter valve at the opening.
  • Connect additional piping to the diverter valve that will carry water outside. Make sure to use the appropriate PVC or ABS pipes.
  • Run the pipe through the wall or underground until reaching the exterior filtration components.

Getting the diverter valve in place and running the initial pipes is a straightforward process with a little handywork. Just be sure to shut off water supplies before cutting into any existing plumbing!

Filtration System

Now that the greywater is flowing outside, it’s crucial to filter out any gunk, particulates, and chemicals before using it for irrigation.

A multi-layer filtration system catches all the undesirables:

  • The first gravel layer distributes water evenly across the filter.
  • Next, a sand layer filters out tiny suspended particles.
  • Finally, another gravel layer collects the filtered water and drains it out the bottom.

You can construct a simple filter using plastic buckets, gravel, and sand. Just make sure to occasionally clean out the filtration media to keep it working effectively.

Strategically placing the filter between the diverter valve and storage tank ensures maximally clean water for irrigation.

Greywater Storage

Now it’s time to collect the filtered greywater. Here are some options:

  • Rain barrels are a popular choice – just make sure to seal the opening.
  • Plastic tanks come in a range of sizes to handle different greywater volumes.
  • The storage tank should have a spigot near the bottom to drain out water.
  • Elevate tanks to utilize gravity, or install a small pump to actively move water.

Proper storage keeps greywater contained and free of excess debris. Just be sure to occasionally empty the tank so it doesn’t overflow!

Dispensing the Greywater

Alright, we’ve made it to the fun part – using your filtered greywater! You have options:

  • Drip irrigation slowly waters garden beds for maximum efficiency.
  • A flooding basin lets you quickly disperse large amounts of water.
  • Attach a garden hose to the storage tank for on-demand watering.
  • With some plumbing work, integrate into an existing sprinkler system.
  • For maximum water savings, reuse greywater to flush toilets.

Whatever dispersion method you choose, take care to avoid direct contact between greywater and edible plants. And don’t drink that stuff either!

Building Your Own Greywater System

Ready to get your hands dirty? Here’s a step-by-step guide to constructing your own system:

Gather Materials

You’ll need piping, connectors, filtration media, storage tanks, and irrigation components. Here’s what a basic setup requires:

  • Diverter valve & accessories
  • PVC pipes & elbows
  • Filter bucket, sand & gravel
  • Rain barrel or storage tank
  • Spigot for drainage
  • Garden hose, drip tubing, etc.

Make sure to measure pipe lengths and get all the right fixture sizes for smooth assembly.

Set Up Water Collection

With the water shut off, cut into the drain pipe from your chosen greywater source. Insert a t-shaped diverter valve into the opening and attach drainage pipes. Clamp everything tightly and check for leaks before turning water back on.

Build Multi-Layer Filter

In a large bucket, layer coarse gravel, sand, and gravel again. Position the bucket beneath the diverter valve so water flows in the top through gravity. Attach a drainage pipe to the bottom.

Link to Storage Tank

Place the storage tank close to the filter and irrigated areas. Attach inlet and outlet pipes – add a pump if needed. Install a spigot near the bottom for easy greywater access.

Connect Irrigation Components

Finally, link up your irrigation system! Run tubing from the spigot to garden beds, a hose, or tie into your main sprinkler line. Consider adding a shutoff valve for easy on/off control.

And that’s it – you now have a fully functional greywater system! Monitor and maintain it over time for maximum water savings.

Maintaining Your Greywater System

Like any irrigation setup, your greywater system needs occasional TLC to keep it working properly:

  • Clean out filters as they accumulate dirt and grime.
  • Inspect all pipes and tanks for leaks and repair as needed.
  • Test greywater frequently for potentially unhealthy contaminant levels.
  • Empty the storage tank on a regular basis to make room for more water.

Take time to check on the system, especially after heavy use or major rainstorms that might clog pipes or filters. A little maintenance goes a long way!


With your new greywater system up and running, here are some final thoughts:

  • Follow all local building codes and regulations related to greywater.
  • Consult irrigation specialists if you need help designing your system.
  • Start small with just one water source, then add on as you get comfortable.
  • Pat yourself on the back for major water conservation – and lower bills!

Reusing water is tremendously satisfying and environmentally friendly. A homegrown greywater system is the perfect way to take control of your water use while keeping the lawn green and garden thriving!

Piping, pumping, filtering – who knew recycling water could be so rewarding? By now you should feel ready to tackle a greywater system in your own home!

With a little planning and elbow grease, you can easily conserve water resources and cut back on utility costs. Plus, you’ll love knowing you did your part to reduce environmental impact.

So don’t hesitate – grab those PVC pipes and get building! Just follow the steps outlined here for constructing a simple, effective system. With a functioning greywater setup, you’ll save water, money, and the planet. Let me know how it goes!