Quick Answer
Greywater recycling — reusing water from showers, baths and laundry for garden irrigation — can save Melbourne households 30,000–60,000 litres of drinking water per year. A simple laundry-to-garden diverter costs $30–$100 and requires no council approval. A full treated greywater system with filtration costs $5,000–$12,000 installed, and may require a planning permit. For most SE Melbourne homes, the laundry diverter is the fastest and cheapest starting point.
What Is Greywater?
Greywater is water that has been used in your home — from showers, baths, bathroom basins, and laundry — but does not contain toilet waste (which is blackwater). In a typical Melbourne home, greywater makes up roughly 50–60% of all household wastewater. Instead of going straight to the sewer, greywater can be captured and used for sub-surface garden irrigation.
Types of Greywater Systems
| System Type | Water Source | Cost | Approval Required? |
|---|---|---|---|
| Laundry-to-garden diverter | Washing machine only | $30–$100 DIY | No — exempted in Victoria |
| Shower diverter (manual) | Shower / bath | $100–$300 installed | No — for sub-surface use |
| Basic greywater treatment system | All greywater except kitchen | $2,000–$5,000 installed | Yes — EPA and council |
| Full treated greywater system | All greywater sources | $5,000–$12,000 installed | Yes — EPA and council permit |
Is Greywater Recycling Worth It in Melbourne?
Potential Water Savings
A standard Melbourne household uses approximately 150–180 litres per person per day. Of that, showers account for roughly 30 litres, laundry 50 litres, and baths 80+ litres per event. A family of four can generate 300–400 litres of reusable greywater daily — enough to irrigate a medium-sized suburban garden through Melbourne’s dry summer months without touching the mains supply.
| Water Source | Daily Volume (4-person home) | Annual Potential Saving |
|---|---|---|
| Laundry (washing machine) | 100–150 L | 36,000–55,000 L |
| Showers (4 people) | 120–160 L | 44,000–58,000 L |
| Baths (occasional) | 0–80 L | Varies significantly |
Financial Payback
At Melbourne’s tiered water pricing (roughly $2.50–$3.50 per 1,000 litres for Step 2 usage), saving 40,000 litres per year equates to around $100–$140 off your annual South East Water or Yarra Valley Water bill. A $30 laundry diverter pays for itself in a few months. A $10,000 treated system takes 50–70 years to recoup costs from water savings alone — making it viable only if you value environmental benefit or anticipate future water restrictions.
Victorian Rules and Permits
Victoria’s greywater reuse rules are governed by the Environment Protection Authority Victoria (EPA) and your local council. Key rules:
- Laundry-to-garden diverters are exempt from EPA permits if water goes directly to the garden sub-surface and is not stored. No permit required in Victoria.
- Basic and treated greywater systems require an EPA Works Approval and often a building permit from your local council (Casey, Cardinia, Frankston, Mornington Peninsula, Greater Dandenong).
- Greywater must not pool on the surface, run into drainage channels, or reach any waterway.
- During Stage 2 or higher water restrictions, greywater rules may be temporarily superseded — always check the current restriction status with your water utility.
Tips and Gotchas
- Start with the laundry diverter. It’s the cheapest, easiest entry point. Install one before investing in anything more complex — you’ll quickly learn how much water your household generates and where it’s most useful.
- Don’t use greywater during chemical wash cycles. Bleach, nappy soaker, and heavy-duty detergent washes should go to sewer. Switch the diverter valve back when using these products.
- Sub-surface only for untreated water. Use soaker hose or drip irrigation buried 50–100mm underground. Never spray untreated greywater with a sprinkler — aerosols can carry pathogens.
- Don’t irrigate vegetables that touch the soil. Root vegetables, lettuces, strawberries and other low-growing edibles must not receive untreated greywater. Fruit trees and ornamentals are fine.
- Never store untreated greywater. It must go directly to the garden or back to sewer. Storing it in a tank without treatment breeds bacteria within 24 hours.
- Use phosphate-free laundry detergent. Standard laundry detergents contain phosphates that build up in soil over time. Switch to a certified greywater-safe detergent like Aware or Earth Choice.
- Check your soil drainage first. In SE Melbourne’s heavy clay areas, a percolation test before installing a treated system will save you expensive drainage problems later.
- Contact your water utility. South East Water and Yarra Valley Water both have greywater resources and sometimes offer rebates for greywater system installation — check before you buy.
Local Resources
- South East Water — Greywater — Victorian rules and rebate information for SE Melbourne
- EPA Victoria — Greywater — official permit requirements and approved system types
- Yarra Valley Water — greywater guidance for northern Melbourne suburbs
- Bunnings Warehouse — laundry diverter valves, soaker hose, greywater-compatible drip irrigation kits
- Reece Plumbing — plumbing components for laundry diverter installations
Frequently Asked Questions
Do I need a permit to install a greywater system in Victoria?
For a basic laundry-to-garden diverter that sends water directly to the garden with no storage, no permit is required in Victoria. For any system that stores, filters, or treats greywater, you need EPA Works Approval and likely a council building permit. Contact your local council (Casey, Cardinia, Frankston, etc.) for specifics.
Can I use greywater on my vegetable garden?
Only on fruit trees and tall vegetables where fruit doesn’t touch the ground (tomatoes on stakes, corn, capsicum). Do not use untreated greywater on root vegetables, lettuces, strawberries, herbs, or any produce eaten raw. Treated greywater from an approved system has broader permitted uses.
How much does a laundry-to-garden diverter cost?
A DIY laundry diverter valve costs $30–$100 from most hardware stores and takes 30–60 minutes to install — just a length of flexible hose and a diverter valve fitted to the laundry standpipe. No plumber required for the basic type. A plumber-installed shower diverter runs $150–$300 including labour.
What laundry detergent is safe for greywater reuse?
Use phosphate-free, sodium-free detergents certified as greywater-safe. Brands including Aware, Earth Choice, and Omo Sensitive are widely recommended by water utilities. Avoid bleach-based products, nappy soakers, and heavy whitening agents — switch the diverter valve to sewer during those wash cycles.
Will greywater recycling work in Melbourne’s clay soils?
Yes — SE Melbourne’s clay soils actually work well for sub-surface drip irrigation because water distributes slowly and doesn’t run off. Avoid ponding by keeping irrigation rates low and not applying greywater when soil is already saturated (typically June–August in most SE Melbourne suburbs).