The Most Ignored Part of Every Van Build
Search "van build guide" and you will find thousands of posts on solar, batteries, and bed layouts. Grey water — where the water from your sink goes — is mentioned briefly if at all. Then van lifers discover it is a genuine problem that affects where they can camp, what facilities they need, and whether they are actually legal or not.
This guide covers everything grey water, specifically for Australian conditions and regulations.
What Is Grey Water and Why Does It Matter?
Grey water is waste water from sinks, showers, and cooking — everything except toilet waste (which is black water). In a van build, it is the water that drains from your kitchen sink and any washing facilities.
It matters for three reasons:
- Legal: Dumping grey water inappropriately in national parks, council reserves, and some state forests is illegal and can result in fines
- Environmental: Soap, food particles, and cleaning chemicals damage vegetation and soil ecosystems when concentrated
- Practical: Without a system, you are either carrying large containers to dump, rigging improvisational solutions, or leaving a wet mess wherever you camp
Australian Regulations: What the Law Actually Says
The rules vary by state and by land type, but the consistent principle is:
- National parks: No grey water disposal on the ground. Must be retained and dumped at a dump point.
- State forests: Most allow dispersed grey water disposal if it is through a filter/dispersal system and away from waterways
- Council reserves: Varies enormously by council. Many require self-contained certification for extended stays
- Caravan parks: Always have dump points for grey water
- Private property (with permission): Generally acceptable with a proper dispersal system
Self-contained certification in New Zealand requires a proper grey water retention system. In Australia, "self-contained" for CMCA certification means a grey water tank, pump, and disposal hose. Worth getting if you plan extended travel on strict sites.
Your Practical Options
Option 1: The Bucket Method
A 10–15L bucket under the sink that you empty at dump stations. Cost: A$8–15. Completely effective. Inelegant but used by a surprising number of experienced van lifers who have tried more elaborate systems and returned to this.
Pros: Zero plumbing, easy to empty, you can see exactly how full it is, easy to clean.
Cons: Visible under the sink (aesthetic), requires regular emptying (every 2–3 days for a solo user), manual process.
Option 2: A Dedicated Grey Water Tank
A food-grade polyethylene tank (10–25L is standard for a van build) plumbed to your sink drain with a ball valve outlet at the bottom of the tank. You drain the tank at dump stations via the valve.
Components needed:
- Food-grade tank (Polymaster, Clark Tanks, or similar): A$35–80 depending on size
- 40mm drain fitting for the sink outlet: A$8
- 40mm flexible hose to the tank: A$15–25
- Ball valve outlet at tank base: A$12
- Garden hose fitting for dump station connection: A$8
Total cost: A$80–130. Installation: 2–3 hours for someone comfortable with basic plumbing.
Pros: Contained, neatly integrated, connects to standard dump station hoses.
Cons: Requires mounting space, needs emptying every 3–5 days for solo use.
Option 3: Grey Water Dispersal System
Water from the sink drains through a coarse filter (to remove food solids), then through a sock filter into the ground at a slow enough rate that it disperses without pooling. Legal in many state forest areas. Not legal in national parks or sensitive environments.
The standard design: a 20L drum with a coarse mesh filter at the top and a series of holes drilled in the lower half, buried 200mm in the ground when camping. When you leave, you dig it out, and the filtered water has been slowly dispersed.
This approach works well on a budget for free campers who spend most nights in state forests. It requires enough space to bury the drum, which is not available at all camps.
Option 4: Composting and Direct Outdoor Disposal
For van lifers using eco-friendly, phosphate-free soaps and minimal cleaning chemicals: grey water from washing fruit, vegetables, and hands with pure soap is relatively benign and can often be poured directly onto vegetation well away from waterways. Regulations still apply — this is not an excuse to dump near campsite facilities or waterways — but the environmental impact of pure-soap grey water disposed carefully is genuinely minimal.
Use Dr. Bronner's or another phosphate-free soap if this is your approach.
Reducing Grey Water Volume
The best grey water solution is generating less grey water:
- Washing up in a basin: Rather than running water, fill a 5L basin and wash everything in it. This generates a fixed, known volume of grey water rather than a continuous flow.
- Rinsing with a spray bottle: A spray bottle for rinsing uses a fraction of the water that a running tap uses.
- Biodegradable wipes for basic cleaning: Eliminates much of the washing-up grey water for solo travellers on short trips.
- Camp showers at facilities: Rather than showering in the van, use camp shower facilities when available. Eliminates shower grey water entirely.
A solo van lifer who washes up in a basin generates approximately 4–6L of grey water per day. Managed in a 15L tank, this requires emptying every 2.5–3 days — a manageable frequency at most camping areas.
Dump Stations: Finding and Using Them
Australia has an expanding network of dump stations — facilities where you connect your grey water hose and drain your tank. Most holiday parks offer dump station access to non-guests for A$5–10. Many councils have free dump stations in regional towns.
Finding them: the WikiCamps Australia app has a dedicated dump station filter. The Camps Australia Wide dump station database is also comprehensive. Before heading to a remote area, check dump station locations for your route and plan your tank size accordingly.
Sink Design Considerations
The grey water system starts at the sink drain. A few design decisions that make your life easier:
- Use a 40mm drain fitting rather than a standard household 32mm — it blocks less easily with food particles
- Install a hair/food strainer at the drain outlet — catches solids before they enter your tank and smell
- Make your grey water tank accessible for cleaning — scale and food residue build up and need quarterly removal
- A ball valve on the tank outlet rather than a simple open/close plug — much easier to control flow at dump stations
Building a Grey Water Tank System: Step-by-Step
For those who want a proper integrated grey water system rather than the bucket method, here is a complete construction guide:
What You Need
- Food-grade polyethylene tank 15–20L (Polymaster 15L tank: A$45)
- 40mm drain fitting with rubber seal (plumbing supply, A$8)
- 1.5m of 40mm flexible hose (A$12)
- Hose clamps x4 (A$6)
- 40mm ball valve (A$12)
- Camlock coupling for dump station connection (A$8)
- Tank vent (air inlet prevents vacuum lock when draining): A$6
Total materials: approximately A$95–120
Installation Steps
- Determine your tank mounting location — ideally below the sink level to allow gravity drainage, and accessible from outside the van for emptying. Under the van body or in a cabinet with external access are both common.
- Cut the drain hole in the tank top for the 40mm fitting. Use a 44mm hole saw. Install the fitting with the rubber seal to prevent leaks.
- Install a tank vent in the top of the tank — a small fitting that allows air to enter as water drains out. Without this, a vacuum lock prevents proper drainage.
- Connect the flexible hose from your sink drain to the tank inlet fitting. Use hose clamps at both ends.
- Install the ball valve at the lowest point of the tank. This is your drain valve for dump stations.
- Install the camlock coupling on the outlet side of the ball valve. Standard dump stations accept this fitting.
- Mount the tank securely — use stainless steel brackets or custom timber mounts. A full 15L tank weighs 15kg and must be secured against road vibration and acceleration loads.
Maintenance
Grey water tanks accumulate food residue and soap scum that smells if not managed. Monthly maintenance:
- After emptying at a dump station, pour 2L of water with a tablespoon of white vinegar through the system
- Every 3 months, use a dilute bleach solution (1 tablespoon bleach per 10L water) as a sanitiser
- Install a hair trap at the sink drain to prevent solids entering the tank — these need clearing weekly
Self-Contained Certification in Australia
Unlike New Zealand, Australia does not have a nationally consistent self-contained certification scheme. However, the CMCA (Campervan and Motorhome Club of Australia) runs a voluntary scheme that is accepted at many camping areas and provides proof of genuine self-containment.
CMCA self-contained certification requires:
- A grey water retention tank plumbed to all sinks and showers
- A proper cassette toilet or composting toilet (no direct ground discharge)
- Fresh water storage of at least 40 litres
- The ability to demonstrate the system to an inspector
The certification costs A$80–120 and is valid for 3 years. It opens access to "self-contained only" areas, particularly in New South Wales coastal councils, and is worth pursuing for serious van lifers who want maximum camping flexibility.
Kitchen Design to Minimise Grey Water
The grey water problem is significantly smaller if your kitchen generates less of it:
The Basin Method
Rather than a full-size kitchen sink with running water, many minimalist van builds use a 7–10L basin as the primary washing vessel. Fill the basin with a small amount of water, wash everything in it, and tip the entire 7L into your grey water container. This generates one fixed, known volume of grey water per washing session rather than an unpredictable running-water amount.
The psychological adjustment: it feels more limited initially. After two weeks, most van lifers find it completely natural and are surprised how rarely they miss running water over a full sink.
Dry Cleaning Options
For periods when grey water management is challenging (very remote areas, during water restrictions at free camps):
- Reusable cloth wipes for plates and cookware before washing — reduces the volume of food-contaminated water significantly
- Stainless steel pots with minimal oil used for cooking generate less washing residue than ceramic-coated pans
- One-pot cooking reduces the total washing load
Dump Station Network in Australia
The network of dump stations in Australia has expanded significantly in recent years. Current best sources:
- WikiCamps dump station filter: The most current and comprehensive listing, updated by community members
- Camps Australia Wide: Book or app, comprehensive dump station database with GPS coordinates
- Free dump stations: Many regional councils provide free dump points near town centres as tourism infrastructure. These are often not well-publicised — local visitor information centres know where they are.
- Holiday parks: Almost all accept dump station use for non-guests at A$5–10 per visit. Worth having a list of holiday parks on your route as backup dump options.
Planning rule: never let your grey water tank get above 80% before identifying your next dump point. Running out of grey water capacity and having nowhere to empty is one of the most uncomfortable van life situations and entirely avoidable with simple planning.
Troubleshooting Grey Water Problems
Smell from the Tank
The most common grey water complaint. Causes and solutions:
- Food solids in tank: Install a better trap at the sink drain. Clean the trap weekly without fail.
- Tank not fully draining: The ball valve drain may not be at the lowest point of the tank. If water pools and sits, it ferments. Ensure the drain point is truly at the bottom.
- Biofilm build-up: Monthly vinegar rinse prevents this. If already established, a dilute bleach treatment followed by thorough fresh water rinse removes it.
- Warm weather fermentation: Grey water ferments faster in heat. In summer, empty the tank every 48 hours rather than every 3–4 days. Add a tablespoon of baking soda to the tank after emptying.
Slow Drainage from Sink
If your sink drains slowly, the blockage is almost always at one of three points: the hair trap at the drain, a kink in the flexible hose, or a partial blockage in the 40mm hose run. Inspect and clear in order. A flexible drain snake (A$15–20) clears hose blockages effectively.
The Composting Toilet Question
Grey water management is much simpler without a toilet in the van build — a surprisingly large number of van lifers manage perfectly without one. However, for those who want on-board facilities, composting toilets (Nature's Head and Air Head are the two most popular) eliminate black water entirely and reduce the grey water burden to sink water only.
A composting toilet costs A$1,200–1,800 installed and requires periodic emptying of the separated liquid and solid waste. The solid compost can be disposed of in most composting facilities or buried 30cm+ deep away from water sources. The liquid requires dilution (1:8 ratio with water) and can be applied to vegetation at least 50m from any water source.
For van lifers who camp frequently in national parks where facilities are unavailable, the combination of a composting toilet and a properly managed grey water system represents genuine self-containment — and access to areas that otherwise require facilities.
When You Travel With Others
Grey water volume scales directly with the number of people using the van. A solo van lifer generating 4–6L per day generates 8–12L per day as a couple. This changes the tank capacity requirements and emptying frequency significantly.
For couple van life: a 25L grey water tank (rather than 15L) and a 3-day emptying discipline works well. During van build design, sizing the grey water system for your intended occupancy rather than solo use prevents the frustration of a constantly-full tank.
The Bottom Line on Grey Water
Grey water management is the van build element that most clearly separates responsible van life from its reputation problem. Irresponsible dumping of grey water at free camping spots is one of the main reasons councils and land managers restrict van access to popular areas. Every van lifer who manages their grey water properly is preserving access for everyone.
The simplest approach that works for most van lifers: a 15L food-grade tank, a quarterly vinegar clean, emptied at dump stations every 2–3 days. It takes 3 hours to build, costs A$100 in materials, and solves the problem permanently. There is no good reason not to have this system in a van that anyone is living in seriously.