75L Underslung Fresh Water Tank & Backfill Kit – Ducato Relay Boxer 06–26

💧🚐 This 75 litre underfloor water tank has been purpose-designed for the L2, L3, and L4 models of the Fiat Ducato, Citroën Relay and Peugeot Boxer (>2006–2026). Suitable for use as a fresh water supply tank, it is ideal for campervan and motorhome conversions.

Manufactured from durable, corrosion-resistant polyethylene, the tank features a matt black finish for a discreet and long-lasting underfloor installation. Its hygienic, algae-resistant construction ensures reliability for long-term van builds.

A large threaded access hatch is fitted on the top of the tank, allowing the installation of pumps, internal accessories or sensors, and providing access for periodic cleaning.

Fitting Instructions

This tank installs widthways (driver side to passenger side) in the cavity between the two chassis members, located directly behind the exhaust silencer.
The service hatch must face upward, with the corner cut-out positioned around the handbrake cable.

Due to the handbrake cable location:

L2/L3 models can fit one 75L tank underneath

XLWB / L4 models can fit two tanks, provided no aftermarket modifications occupy the mounting space

Additional Benefits of the Backfill System

This backfill system has been fitted to many conversions, and has been extensively proven. The faceplate uses a universal fitting design, meaning it can be mounted anywhere suitable on your van—without the need to cut a hole in the bodywork. This makes the system ideal for both new conversions and retrofitting to existing vehicles.

As well as being easy to install and quick to use, the backfill system offers additional practical advantages:

Can be used as a jet wash feed tank (as long as your jet wash is capable of drawing water)

Doubles as a water outlet, allowing you to empty your tank when required without needing to install a separate drain tap (great for winterising)

Reduces installation complexity by combining multiple functions into a single fitting

Keeps your van exterior clean and unmodified, thanks to the no-cutout design

What’s Included-

1 × 75L Water Tank (L: 1000mm, W: 300mm, D: 225mm)

1 × 1/2" Elbow for attaching the breather pipe

2 × 1/2" Straight for connecting the blue pipe

1 × 1m long 1/2" Breather Pipe

1 × 2m long 1/2" Blue flexible water pipe

1 × Backfill point with isolator valve

4 x Jubillee clips to secure the pipes

1 x Universal tank/strap fitting kit & fixings

⚠️ Important Information

Water level senders are also available, including models compatible with Victron & SRNE systems (Click Here)

Tank may contain traces of water on arrival—this is normal due to leak testing.

Please ensure the tank is fully cleaned before use.

📏 Specifications

Capacity: 75 litres

Dimensions: 1000mm (L) × 300mm (W) × 225mm (H)

Dry Weight: 5.40kg