Reusing Water in the Garden: Greywater, Rainwater & Recycled Water

Reusing water in the garden can help reduce your reliance on drinking-quality mains water while making better use of water that's already available around your home.

From collecting rainwater to redirecting suitable household greywater or using a dedicated recycled water supply, there are several ways Australian households can use alternative water sources to keep lawns and gardens hydrated.

The right option depends on your home, garden, local regulations and the type of water available to you. Understanding the difference between greywater, rainwater and recycled water is an important place to start.

What types of water can you reuse in the garden?

Not all reused water is the same.

Greywater is wastewater generated from household activities such as showers, baths, hand basins and laundries. It doesn't include toilet water, and kitchen wastewater is generally excluded from untreated household greywater reuse because it can contain higher levels of food waste, grease and contaminants.

Rainwater is water collected from rainfall, usually from your roof and stored in a rainwater tank. It can provide an additional water source for lawns, gardens and other suitable household uses.

Recycled water has been treated for reuse and, in some Australian residential developments, is supplied to homes through a separate pipe network. Residential recycled-water plumbing and outlets are clearly differentiated from drinking-water systems, commonly using purple or lilac identification.

Each can play a role in creating a more water-efficient garden, but they need to be used appropriately.

How to use greywater in the garden

Greywater can provide a useful secondary water source for lawns, trees and garden beds when it is handled correctly.

Common household sources include water from:

• showers and baths

• bathroom hand basins

• laundry tubs

• washing machines.

Greywater can contain detergents, salts, organic matter and microorganisms, so it's important to think about what has gone into the water before applying it to your garden. Australian Government guidance recommends choosing low- or no-sodium laundry products and minimising household chemicals where greywater will be reused.

If you're planning to reuse laundry water, explore Nylex's greywater hoses, which are designed to help direct water from suitable household outlets.

Using washing machine water in your garden

One of the most practical sources of household greywater is the washing machine.

A simple diversion setup can direct suitable washing machine discharge towards parts of your garden instead of sending it straight to the sewer.

The existing Nylex greywater guide includes a useful demonstration from horticulturalist Chloe Thomson showing how a greywater diversion system can be set up using Nylex products.

Where greywater is distributed through a suitable dispersion system, position it so water is spread across the required area rather than collecting in one place. Subsurface or below-mulch distribution can help spread untreated greywater more evenly while reducing direct human contact.

Greywater do's and don'ts

There are a few important precautions to follow when reusing greywater.

Do use greywater promptly

Untreated greywater shouldn't be stored for extended periods. If it is stored for more than 24 hours, it can begin to turn septic and requires treatment and disinfection before reuse.

For a simple household diversion system, the aim should generally be to use the water shortly after it is produced.

Do choose garden-friendly household products

What goes into your washing machine or shower eventually ends up in the greywater.

Where possible, choose products that are lower in salts and phosphorus and avoid disposing of harsh household chemicals into water that will later be used on plants.

Don't allow greywater to pool

Greywater should be distributed across an appropriate area rather than allowed to pond or run off your property.

Too much reused water can waterlog soil and introduce more salts or nutrients than plants and soil can absorb. Adjust how much you use according to soil conditions, rainfall and what you're growing.

Be cautious around edible plants

Greywater rules and recommendations can vary depending on where you live and whether the water has been treated.

Australian Government guidance recommends avoiding reused wastewater on vegetables that will be eaten raw because pathogens may still be present.

For vegetable gardens and other edible plants, check the requirements of your local council, water authority or state health department before using greywater.

Can you use greywater on all plants?

Not necessarily.

Some plants and soils are more sensitive to the salts, nutrients and other substances that may be present in greywater.

Watch how plants respond over time, avoid repeatedly applying greywater to one small area and alternate with fresh water where appropriate.

You should also consider whether the soil is already wet. Applying greywater to saturated soil can lead to waterlogging and unnecessary runoff.

For more advice on determining when plants actually require water, see our guide to effective garden watering.

What about shower and bath water?

Water from showers and baths can also form part of household greywater.

Simple collection methods may be suitable in some circumstances, while permanent diversion or treatment systems can involve plumbing and regulatory requirements.

Rules differ between Australian states and councils, so check your local requirements before installing or altering a greywater system. In some jurisdictions, certain plumbing work must be undertaken by a licensed plumber.

Reusing rainwater in the garden

Rainwater is another valuable source of water for Australian gardens.

Rainwater collected from a suitable roof catchment can be directed into a tank and used later for garden watering. This lets you store some of the water that falls on your property rather than relying entirely on mains water when the garden needs a drink.

Rainwater tanks can be particularly useful because garden demand often increases during periods of lower rainfall.

If you use stored rainwater for garden irrigation, the way you apply it still matters. Deep, targeted watering and adjusting your routine to current soil conditions can help make the water you've collected go further.

You can also use a rain gauge to monitor how much rainfall your garden has already received before deciding whether additional watering is required.

For more ways to adjust watering around weather and seasonal conditions, see our watering tips for Australian summers.

What is recycled water?

Recycled water is different from household greywater.

It is wastewater that has gone through a treatment process so it can be safely used again for specified non-drinking purposes.

Some Australian residential areas have a separate recycled-water supply connected to homes. Depending on the system and water quality, this water may be used for applications such as garden watering and toilet flushing.

Recycled water supplied to residential properties isn't drinking water and must remain clearly separated from the drinking-water system. Purple or lilac pipes, taps, meters and warning signage are commonly used to identify these systems.

Nylex offers a dedicated range of recycled water products, including colour-coded hoses, fittings, sprinklers and other watering equipment to help clearly distinguish recycled-water use.

Using recycled water in your garden

Where recycled water is available at your property and approved for garden use, it can provide an alternative to drinking-quality mains water for lawns and garden beds.

Before connecting watering equipment, identify the recycled-water outlet and make sure you're using equipment appropriate for the system.

Nylex's recycled water hoses use the distinctive colour associated with non-drinking recycled-water systems, making it easier to distinguish them from standard garden hoses.

You should still water according to what your plants need rather than automatically using more water simply because an alternative source is available.

For lawns specifically, our guide to lawn watering in Australia explains how factors such as season, soil and grass type influence watering requirements.

Use the right watering method for reused water

Once you've identified an appropriate water source, think about how that water will reach your plants.

Delivering water closer to the root zone can reduce unnecessary overspray and help you target the parts of the garden that actually need it.

For garden beds, slow watering methods can be particularly useful. Our guide to soaker hoses vs weeper hoses explains how the two systems work and where each is best suited.

Whatever method you use, avoid watering hard surfaces, check the soil before watering and adjust your routine after rainfall.

Reuse water without overwatering

Having an alternative water source doesn't mean your garden always needs more water.

Before using rainwater, greywater or recycled water, check:

• whether the soil is already moist

• how much rain has recently fallen

• the needs of the plants you're watering

• whether water is draining properly

• whether your local area has specific rules for that water source.

Overwatering can be just as problematic as underwatering, so aim to match the amount of reused water with what your plants and soil can absorb.

Watering during cooler parts of the day can also help you use available water more effectively. Read more in our guide to the best time of day to water your garden.

Check your local greywater and recycled water rules

Water reuse requirements aren't identical across Australia.

The rules governing greywater diversion, treatment systems, plumbing work and recycled-water use can vary between states, territories and local councils. Australian Government guidance recommends checking with your local government, water authority or state health department before establishing a wastewater reuse system.

This is particularly important if you're installing a permanent greywater system, storing greywater, altering household plumbing or using reused water around edible plants.

Frequently Asked Questions

What water can I reuse in my garden?

Depending on your home and local regulations, you may be able to use captured rainwater, suitable household greywater or treated recycled water. Each source has different requirements, so make sure you understand what type of water you're using before applying it to your garden.

Can washing machine water be used on the garden?

Washing machine water can be reused as greywater in many situations, provided it's handled appropriately and local regulations permit it. Choose low-salt household products where possible, use the greywater promptly and distribute it over a suitable garden area rather than allowing it to pool.

How long can you store greywater?

Untreated greywater shouldn't generally be stored for more than 24 hours. Beyond this point it can begin to turn septic and should be treated and disinfected before storage and reuse.

Can greywater be used on vegetable gardens?

Extra care is needed around edible plants. Australian Government guidance recommends avoiding reused wastewater on vegetables that will be eaten raw because pathogens may remain even after treatment. Check your state, council or water authority guidance before using greywater around edible crops.

Is greywater the same as recycled water?

No. Greywater is wastewater produced by household activities such as showering and washing clothes. Recycled water has undergone treatment for reuse and may be supplied to homes through a dedicated non-drinking-water network.

Can you use recycled water to water a garden?

Yes, where the recycled water supplied to your property is approved for garden irrigation. The permitted uses depend on the water quality and local supply system, so follow the instructions provided by your water authority.

Is rainwater good for garden watering?

Captured rainwater can provide a useful alternative water source for lawns and gardens and reduce reliance on mains water. The suitability of rainwater for other household purposes depends on the collection system, water quality and local requirements.