Water Tanks for Pressure Washing Rigs

A garden spigot flows 4 to 8 GPM. A commercial machine pulls 5.5 to 10. That gap is why buffer tanks exist, and it is why pumps die young without one. Sun Brite Supply stocks poly water tanks sized for pickup beds and trailers at our Gaithersburg, MD counter. Call 301-519-9274 and we will size your tank before you spend a dollar.

Picking the Right Water Tank for Your Rig

Start with the deficit. If your machine draws 8 GPM and the customer's spigot supplies 5, you fall behind 3 gallons every minute the trigger is pulled. A buffer tank covers that gap while a float valve lets the spigot refill the tank as you work. For most 5.5 to 8 GPM rigs, a 225 gallon horizontal leg tank on a trailer or a 325 gallon pickup tank gets you through a full house wash without waiting on the hose bib.

Weight is the spec people skip. Water runs about 8.3 pounds per gallon, so a full 325 gallon tank is roughly 2,700 pounds before you add the machine, reels, and chemicals. That is past the payload of most half-ton trucks. Run partial fills, or step down to the 225, which sits low and rides at about 1,900 pounds full. Either way, strap it down. An unsecured tank becomes a battering ram at the first hard stop, and a steel support strap costs less than one bodywork estimate. Feed the pump from the tank with a short, fat suction line, 1 inch minimum, with a strainer at the pickup so grit never reaches the valves.

Build Out the Rest of the Rig

• Float valves to auto-refill the tank on the job
• Garden hose pump inlets with filters
• Suction strainers and water filters
• 12 volt pumps for soft wash tanks
• Hose reels to keep the deck clean
• Pressure washer pumps if yours already ran dry
• Soft wash equipment

Local crews can load a tank same day at our Gaithersburg store.

Frequently Asked Questions

Do I really need a buffer tank?

Under 5 GPM on city water, usually not. At 5.5 GPM and up, or on rural wells, yes. The tank absorbs the difference between what the spigot gives and what the pump takes, which stops cavitation.

What size water tank fits in a pickup truck?

Our 325 gallon tank is shaped for full-size beds. Full, it weighs about 2,700 pounds, so it belongs in a 3/4-ton or heavier truck. Half-ton owners should run partial fills or trailer a 225.

Can I feed my pressure washer straight from the tank?

Yes. Plumb a short suction line, 1 inch or larger, from a bottom bulkhead to the pump inlet, add a strainer, and keep the tank higher than the pump so gravity helps the feed.

How do I keep the tank from running dry mid job?

Put a float valve on the fill line from the customer's spigot. It tops the tank off continuously and shuts when full, so you spray while the tank refills behind you.