12 Volt Pumps for Soft Washing

Soft washing runs on chemical, not pressure, and the 12 volt pump is the part doing the spraying. We stock Everflo, Shurflo, and FloJet diaphragm pumps plus the valve and diaphragm kits that keep them alive on bleach. Building a rig or replacing a tired pump? Call 301-519-9274 and tell us your tank size and what you spray. We will size the pump and the battery in the same conversation.

Sizing a 12 Volt Pump for the Work You Do

Flow decides how fast you cover a roof or a house wall, so pick GPM first. A 1 to 2 GPM pump handles spot treatment, fence lines, and small batch rigs. A 3 to 4 GPM pump covers most house wash setups. Roof rigs that need to reach a second story and keep a wide wet edge want 5.5 to 7 GPM. That is also the practical ceiling for this class of pump. A 12 volt diaphragm pump tops out around 7 GPM and about 100 PSI, and that is plenty, because the sodium hypochlorite does the cleaning while the pump just delivers it.

Pressure ratings matter less than they look. The 60 to 100 PSI these pumps make is enough to throw a stream 25 to 35 feet with the right tip and hose. If you need more reach than that, the answer is usually a booster tip or a bigger pump, not more PSI.

Amp Draw and Battery Math

Every jump in GPM costs you amps. The small 1 GPM units pull about 4 amps, the 4 GPM class pulls around 13, and a 7 GPM pump draws roughly 23 amps at load. Run that 23 amp pump off a 100 amp hour deep cycle battery and you get about 4 hours of trigger-down time, which usually stretches across a full day since nobody sprays nonstop. Two rules save a lot of service calls. Use a true deep cycle battery, not a starting battery, and wire the pump with heavy gauge cable and clean connections. Low voltage makes these motors run hot, and heat is what kills them.

Why These Pumps Start and Stop on Their Own

Nearly every 12 volt sprayer pump is a demand pump. A pressure switch on the head watches the outlet. Close the gun and pressure climbs until the switch cuts the motor. Open the gun, pressure drops, and the pump restarts. No unloader, no bypass loop to plumb.

Rapid on-off cycling while you spray is the classic complaint. It means the pump is making more flow than the tip can pass, so pressure keeps tripping the switch. Fix it with a larger orifice tip, or step down to a pump matched to your nozzle. Constant running with weak output points the other way, at a clogged inlet strainer, a pinched suction line, or worn valves.

Bleach Eats Cheap Parts

A soft wash pump lives on 12.5% sodium hypochlorite, and the elastomers inside decide how long it lives. Santoprene diaphragms and Viton or EPDM valves stand up to hypochlorite. Generic RV pumps with nitrile guts do not, which is why a bargain transfer pump rarely survives a season on a soft wash rig. Everflo builds its SW series specifically for bleach duty, and Shurflo sells its 8000 series with valve materials to match the chemical.

The habit that doubles pump life costs five minutes. Flush the pump and lines with fresh water at the end of every shift. Bleach left sitting in the head over a weekend crystallizes, chews valve seats, and glues the diaphragm. We sell Santoprene diaphragm kits, EPDM valve kits, and Viton valve kits for Shurflo pumps, so a rebuild costs $22 to $63 instead of the price of a new pump.

12 Volt Pump Lineup

From the Field

Our parts counter tells the real story. We sell far more valve kits and diaphragm kits than we should, and almost every one traces back to bleach left in the pump between jobs. The crews who flush daily rebuild once every year or two. The crews who do not are back every couple months. Second lesson from the counter: the smartest $51 on a soft wash trailer is a spare EF1000 zip-tied next to the main pump. When a diaphragm quits at 9 am on a Saturday, the spare finishes the roof and the rebuild happens Monday.

Related Collections

• Soft wash equipment
• Roof cleaning chemicals
• House washing chemicals
• Chemical hoses
• Chemical strainers
• Water and chemical tanks
• Chemical injectors
• Pump up sprayers
• Pressure washer pumps

Stop by our Gaithersburg counter if you want to see the pumps side by side before you buy.

Frequently Asked Questions

Why does my 12 volt pump keep cycling on and off while I spray?

The pump makes more flow than your tip can pass, so the pressure switch keeps tripping. Move to a larger orifice tip or match a smaller pump to your setup, and the cycling stops.

Will these pumps handle 12.5% sodium hypochlorite?

The soft wash rated models will. Look for Santoprene diaphragms with Viton or EPDM valves, like the Everflo SW series and Shurflo 8000 series. Flush with fresh water after every shift to make them last.

What battery should I run with a 12 volt soft wash pump?

A deep cycle battery sized to your amp draw. A 7 GPM pump pulling 23 amps gets about 4 hours of continuous run from a 100 amp hour battery, which covers a normal spray day. Small 1 to 2 GPM pumps run all day on much less.

How far will a 12 volt pump spray?

With a proper tip, a 5.5 to 7 GPM unit reaches 25 to 35 feet, enough for most two story homes and single story roofs from the ground or a ladder.

Can a 12 volt diaphragm pump run dry?

Briefly, yes. Diaphragm pumps self-prime and tolerate short dry runs, but minutes of dry running heats the head and warps parts. Keep the strainer clean so the pump never starves.

How do I winterize a soft wash pump?

Flush the bleach out, then pull RV antifreeze through the pump and lines before the first freeze. A frozen head cracks, and that is a replacement, not a rebuild.