DSDetailer SetupPlan my setup
All calculators

Free planning tool

Water tank and pressure washer compatibility checker

Compare a mobile detailing tank supply, measured inlet flow and pressure-washer requirements before shortlisting pumps, filters, hoses or fittings.

Use the exact pressure-washer manual and measure delivery at the final hose where it connects to the machine. Pump headline figures do not include losses through the real tank, filter, valves and hose run.

Washer requirement

L/min
Use rated operating flow, not a maximum marketing figure.
L/min
Enter 0 only when the exact model manual gives no figure.
bar
Self-priming and gravity-fed operation are model-specific.
%
Allowance above the larger of operating flow and stated minimum inlet flow.

Real supply path

L/min
Test through the actual outlet, filter, valves, connectors and hose.
bar
Enter 0 if not measured; a bucket flow test does not measure pressure.
L
Use genuinely usable water, not only the moulded tank capacity.

Compatibility screen

The entered figures clear this check

Entered figures clear
Required delivery with reserve10.35 L/min
Measured flow margin+1.15 L/min reserve
Inlet pressure+0.6 bar margin
Theoretical continuous trigger time46.7 min
Tank capacity350 L / 92.5 US gal

The measured flow and any pressure figures entered clear this screening check. The exact model manual, priming method, hose limits and manufacturer approval still control compatibility.

Measure the system—not the label

Run the flow test at the machine inlet.

A pump may advertise enough flow in isolation and still fall short after a small tank outlet, loaded filter, long hose, restrictive connector or height change. Build the same path you intend to use, then measure where the supply hose meets the pressure washer.

  1. 01
    Use the lowest normal tank level

    That is often the more demanding part of the working range. Keep the vehicle level and the tank safely secured.

  2. 02
    Include every restriction

    Fit the production outlet, valves, filter, connectors and full hose length before testing.

  3. 03
    Measure flow over time

    Collect into a marked vessel. Litres collected ÷ seconds × 60 gives litres per minute.

  4. 04
    Check pressure separately

    A bucket test gives flow, not inlet pressure. Use a suitable gauge or competent installer when the manual states a pressure requirement.

The manual remains the authority

Stored-water operation is model-specific.

Some machines support suction from an open container only with a particular priming method, filter, check valve, hose or maximum lift. Others require a pressurised inlet. A result here cannot transfer one manufacturer's instructions to another model.

  • Find the exact model manual and record its inlet flow, inlet pressure and suction or priming instructions.
  • Ask the manufacturer in writing when a required figure or tank-fed arrangement is unclear.
  • Re-test after changing the filter, hose, fittings, pump setting or tank position.
  • Use the 12V water pump selector to turn a confirmed shortfall into a flow-and-pressure duty point.
  • Run the payload check: each litre of carried water adds roughly one kilogram before the tank and fittings.
Primary references and examplesKärcher K 7 WCM manual — model-specific suction instructions Nilfisk MC 2C manual — open-container example Vehicle weights explained — GOV.UK

Build from the requirement

Compare components only after measuring the gap.

These broad Amazon UK searches are starting points. Reject any listing that does not publish the dimensions, ratings and instructions needed to verify it against your full water path. Worldwide readers can use the same checklist with an appropriate local retailer.

Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. The price is unchanged for you. These searches are not endorsements, compatibility approvals or a claim that every result is suitable.