Pressure Washing · Water Planning

Pressure Washer Water Supply & Tank Planner

Plan water volume for a pressure washing job from washer flow, trigger-on time, starting tank water, and incoming supply. Use the optional bucket test to measure a job site's water source before you rely on it.

No sign-upSave in this browserOptional bucket flow testWater-volume planning only

Water supply and buffer tank plan

Enter the flow and water values you expect for one job. This planner uses steady-flow volume math and does not choose equipment or tank size for you.

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Job reference

Optional details for saving, copying, exporting, and printing this plan.

Washer demand and tank setup

Use rated or verified values for the setup you plan to run. Trigger-on time means the estimated total minutes water is actually flowing through the washer.

GPM

Enter the washer flow rate you plan to use.

min

Total estimated minutes the washer is flowing water, not total clock time on site.

gal

Enter the usable water capacity you intend to treat as available.

gal

Must not exceed usable tank capacity.

GPM

Leave blank for no incoming water during trigger-on use.

Optional: Measure your water source

Time how long it takes to fill a known volume at the actual connection point or hose path you plan to use.

Measured supply flow
gal

Use the known container volume actually filled.

sec

Time the fill in seconds.

Formula: GPM = gallons ÷ seconds × 60. Re-test at the job site if hose length, filters, valves, or the connection path changes.

Results

Planning results assume the entered washer flow and incoming supply remain constant during trigger-on time.

Additional water neededExtra water beyond starting tank water and incoming supply during trigger-on use.
Total water requiredWasher GPM × trigger-on minutes.
Starting tank waterWater available in the tank at the start.
Incoming supply rateThe entered or measured source flow used in this plan.
Net tank drawWasher GPM minus incoming supply, never below zero.
Runtime before tank reaches emptyBased on starting tank water and net tank draw.
Water remainingEstimated tank water after the entered trigger-on time, capped at usable tank capacity.
Estimated extra fill timeTime to supply the additional water needed at the entered incoming supply rate.
Estimated full-tank equivalentsAdditional water needed ÷ usable tank capacity. This is a volume comparison, not a refill-count instruction.

Enter the required washer and tank values to calculate the water plan.

Volume planning only. This planner does not verify vehicle payload, axle limits, tank securement, plumbing, pump-feed requirements, backflow protection, equipment compatibility, or whether a water source is safe or adequate for your equipment. Follow manufacturer instructions and applicable requirements separately.

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What this planner does

It compares pressure washer demand with starting tank water and an optional incoming source. It is intended for water-volume planning, not tank selection, pump protection, transport safety, or plumbing design.

How to plan pressure washer water supply

Start with the pressure washer's flow rate in gallons per minute and the estimated trigger-on time for the job. Then enter the usable tank capacity, how much water is in the tank at the start, and any incoming source flow that can replenish the tank while the washer is running.

Total water required = washer GPM × trigger-on minutes
Net tank draw = max(washer GPM − incoming GPM, 0)
Additional water needed = max((washer GPM − incoming GPM) × trigger-on minutes − starting tank water, 0)

Why measure the water source?

A bucket test gives you a job-specific flow estimate instead of relying on an assumed spigot rate. Enter a known container volume and fill time, then use the measured GPM as the incoming supply rate if that matches the setup you plan to use.

How should I read full-tank equivalents?

It compares the extra water volume with your usable tank capacity. For example, 75 gallons of additional water with a 100-gallon usable tank equals 0.75 full-tank equivalents. It does not tell you when to stop, refill, or how many refill stops will be practical.

Does this tell me whether my pressure washer has enough water?

No. It calculates volume from the numbers you enter. Actual system performance can depend on plumbing, hose restrictions, tank layout, feed method, valves, filters, pressure washer requirements, and other job-site conditions.