Grey water is water from your sink and shower. You need somewhere to store it before disposal. Underslung tanks mount under the van, saving interior space.
Why Underslung?
- Space-saving: No interior space used
- Capacity: Larger than interior tanks
- Lower centre of gravity: Better vehicle handling
- Discreet: Not visible from inside
Tank Sizes
- 40 litres: Good for solo travellers
- 60 litres: Good for couples
- 80+ litres: Good for families
Installation
Location
Mount under the van, between the chassis rails. Ensure ground clearance is maintained.
Connections
Connect sink and shower drains to the tank. Use flexible hoses and P-traps.
Venting
The tank needs a vent to prevent pressure buildup. Install a vent pipe.
Drainage
Install a drain valve at the bottom. Connect a hose for emptying.
Disposal
Legal Requirements
In the UK, grey water must be disposed of at designated disposal points. Don't dump it on the ground.
Disposal Points
- Campsites: Most have grey water disposal
- Caravan parks: Usually available
- Motorway service stations: Some have disposal points
- Council tips: Some accept grey water
Tips
- Empty regularly: Don't let the tank overflow
- Use biodegradable products: Minimise environmental impact
- Clean the tank: Flush with clean water after emptying
Maintenance
- Check for leaks: Inspect connections regularly
- Clean filters: If your tank has a filter
- De-ice in winter: Use antifreeze or drain for winter
Conclusion
Underslung grey tanks save interior space and increase capacity. Choose a size that matches your needs, install it properly, and dispose of grey water legally. It's a simple system that makes van life easier.
