A power washer water tank allows you to run a pressure washer without a direct garden hose connection. This is useful for remote locations, mobile washing, or areas with limited water access. This guide covers tank types, sizing, setup, safety, and best practices.
Why Use a Water Tank?
- Remote jobs: Clean equipment, barns, fences, or vehicles far from a spigot.
- Mobile washing rigs: Common for contractors who need portable water.
- Water restrictions: Use stored water where municipal supply is limited.
- Backup supply: Useful in rural areas or during events.
Types of Water Tanks
| Type | Capacity | Best For | Notes |
|---|---|---|---|
| Polyethylene tank | 15–325+ gal | Most rigs | Light, affordable, corrosion-resistant |
| IBC tote | 275–330 gal | Bulk water | Stackable, common, needs frame support |
| Water bladder | 25–1000 gal | Portable/soft storage | Collapsible, easy to transport empty |
| Stainless tank | Varies | Potable/long-term | Durable, expensive |
| Trailer-mounted tank | 100–1000 gal | Mobile rigs | Integrated with pump/hose reel |
Sizing Your Tank
Tank size depends on GPM and job duration. Estimate: gallons = GPM × minutes. For example, 3 GPM × 60 minutes = 180 gallons. Add buffer for rinsing and delays.
- Electric small washers (1–1.8 GPM): 15–50 gal often sufficient.
- Mid gas (2–3 GPM): 50–150 gal for extended work.
- Commercial (3.5–5.5 GPM): 150–300+ gal for all-day use.
Gravity Feed vs Pump Feed
Most pressure washer pumps are not designed to suck water from a tank sitting on the ground unless properly configured.
- Gravity feed: Tank must be elevated above the pump inlet (ideally 2–4 feet minimum; more is better) to provide positive head pressure.
- Transfer pump feed: Use a dedicated water transfer pump to push water from tank to pressure washer inlet. This is most reliable for large tanks on the ground.
- Avoid long suction hoses: Short, large-diameter suction hose minimizes cavitation.
Setup Guidelines
- Elevate tank: If gravity feeding, mount tank on a stand/trailer high enough for positive head.
- Use large suction hose: 3/4″ or 1″ suction hose is better than thin hose.
- Install inlet strainer: Prevent debris from entering the pump.
- Keep suction short: Minimize vertical lift and horizontal run.
- Prime if needed: Some setups require priming the suction line before starting.
- Avoid air leaks: All suction fittings must be airtight.
- Use a float valve or vented tank: Vented tanks prevent vacuum lock.
Safety and Best Practices
- Secure tank: Strap tanks on trailers/trucks to prevent shifting.
- Clean water only: Avoid pond/lake water without heavy filtration; debris damages pumps.
- Monitor water level: Don’t run tank empty while pump is running.
- Avoid cavitation: If pump surges or sounds odd, check suction.
- Winterize: Drain tank, hoses, and pump to prevent freezing.
- Chemical considerations: Don’t store harsh chemicals in potable water tanks.
- Local regulations: Check rules for hauling/using water in your area.
Troubleshooting Tank-Feed Issues
| Issue | Cause | Fix |
|---|---|---|
| Pump won’t pull water | Tank too low, air leak, clogged strainer | Elevate tank, check fittings, clean strainer |
| Pulsing/Surging | Cavitation, partial blockage | Increase head, use larger suction hose |
| Air bubbles in line | Loose suction fittings | Tighten and seal all suction connections |
| Low pressure | Insufficient inlet flow | Add transfer pump or increase elevation |
| Pump overheating | Running dry/cavitating | Stop immediately, fix suction |
Maintenance Tips
- Clean tank periodically: Rinse to prevent algae/slime buildup.
- Inspect hoses/fittings: Check for cracks, leaks, or collapse.
- Check vent: Vented cap must be clear.
- Store dry when empty: Prevent mold in bladders/tanks.
- Protect from UV: Use UV-stabilized tanks or cover them.
Frequently Asked Questions
Can I connect a tank directly to my pressure washer?
Only if you provide adequate inlet flow. Gravity feed from an elevated tank or a transfer pump is usually needed.
How high should I elevate the tank?
At least 2–4 feet above pump inlet for most units. Higher elevation gives better flow; follow pump manufacturer guidance.
What size suction hose do I need?
Use the largest diameter practical (3/4″ minimum; 1″ better for high GPM). Keep it as short as possible.
Can I use lake or creek water?
Not recommended without a robust filtration system. Sand/silt will damage the pump quickly.
Is an IBC tote good for pressure washing?
Yes, if secured, elevated or fed by transfer pump, and cleaned regularly. Ensure it’s food-grade if using potable water.