VW T6 & T6.1 Underslung Water Tank with Backfill Fill System

The Problem

You want a fresh water solution for a VW T6 or T6.1 Kombi camper conversion that frees up the internal cupboard space normally taken by 20-litre fresh and grey water tanks, and you need a way to accurately measure how much water has been loaded into an underslung tank that you cannot see inside.

Solution

1. Mount the stainless steel bracket kit in a suitable position under the van, clear of the spare wheel and any underslung gas tank. Source the tank and matching stainless bracket kit as a set so the fixing points line up (note the brand and part number of the kit you buy and verify the part number before ordering, as several suppliers make T6-specific underslung kits).
   • Exclusions: this tank is not compatible with 4Motion models or vans fitted with an underslung gas tank. The fitment is the same for T6 and T6.1 (the underbody and chassis rails are common to both generations), but confirm clearance against your own spare wheel carrier and exhaust routing before drilling, as this can vary by trim.
2. Drill holes in the tank at the desired fitting locations: place the breather inlet as high as possible, the water feed outlet as close to the bottom as possible, and the water inlet also near the bottom.
3. Wrap the threaded fittings with PTFE thread-seal tape (3 to 4 turns, in the direction of tightening) before fitting. This is a potable water system and unsealed threads are a common leak point. Insert the fittings into the drilled holes with the rubber seals on the outside of the tank, then tighten the bolts from inside using the tank's access hatch. Do not overtighten and crack the tank.
4. Warm the blue flexi pipe in hot water to make it more flexible, then push it fully onto the tank fittings and secure with jubilee clips. Buy the flexi pipe to match the spigot size of your fittings (confirm the diameter — commonly 12mm or 15mm — against the fittings supplied with your kit before ordering).
5. Assemble the backfill system: click the 15mm to 1/2-inch adapter into the heavy-duty hand valve, place the aluminium bracket on the 3/4-inch BSP end, then screw the Hozelock fitting on tightly over the thread. Apply PTFE tape to the BSP thread first.
   • Tighten the Hozelock fitting with pliers rather than by hand to ensure a leak-free seal.
6. Connect the Shurflo pump and inline water filter to the water feed outlet pipe running into the van. Match the pump and filter to your system: a typical camper unit is a 12V Shurflo diaphragm pump in the region of 7–11 litres/min with an inline strainer/filter sized to the pump's ports (verify the exact model and flow rate before ordering to ensure the filter and pump are compatible).
7. Attach an inline digital water flow meter to the Hozelock filling point so you can measure exactly how many litres are loaded into the tank before each trip.