How Much Water Do You Actually Use?
The most common mistake in setting up a mobile detail rig is under-sizing the tank. Before buying anything, calculate your actual water consumption per job:
| Service Type | Water per Vehicle | 100-gal Tank Supports |
|---|---|---|
| Waterless / rinseless wash | <1 gallon | 100+ vehicles |
| Hand wash (low-flow technique) | 5–10 gallons | 10–20 vehicles |
| Traditional hand wash + rinse | 15–25 gallons | 4–6 vehicles |
| Full detail with pressure pre-rinse | 25–40 gallons | 2–4 vehicles |
| Full detail + engine bay | 35–50 gallons | 2–3 vehicles |
| Fleet washing (commercial) | 40–80 gallons/vehicle | 1–2 vehicles |
Rule of thumb: Size your tank for at least half a day of operation without refilling. If you do 4 full details per day at 30 gallons each, you need 120+ gallons. A 150-gallon tank gives you comfortable margin.
Tank Size Recommendations by Rig
Solo Operator — Truck Bed Setup
| Best tank | 35-gal or 65-gal horizontal leg tank (fits most truck beds) |
| Weight when full | 35-gal: ~300 lbs · 65-gal: ~550 lbs |
| Best for | 2–4 full details per fill; rinseless wash operations |
| Amazon option | 35-gal horizontal tank → |
A 35-gallon horizontal tank sits flat in a truck bed and doesn't require a trailer. Paired with a 12V demand pump and a hose reel, this is the minimum viable setup for a mobile detail business doing 2–3 cars per day without access to a water hookup. Add a second 35-gallon tank on the other side of the bed to double your capacity without adding trailer complexity.
Part-Time or Growing Business — Enclosed Trailer
| Best tank | 100-gal or 150-gal vertical poly tank in enclosed trailer |
| Weight when full | 100-gal: ~850 lbs · 150-gal: ~1,270 lbs |
| Best for | 4–8 full details per fill; half-day operations |
| Amazon options | 100-gal vertical → · 150-gal vertical → |
Full-Time Commercial Operation
| Best tank | 200–500 gal vertical poly on a dedicated equipment trailer |
| Best for | Full-day fleet operations; 6–15+ vehicles per fill |
| Trailer guide | Water Tank Trailers Guide → |
Pump Selection
Your pump choice depends on what services you offer:
| Pump Type | PSI | GPM | Power | Best For | Price Range |
|---|---|---|---|---|---|
| 12V demand pump | 40–60 PSI | 3–5 GPM | 12V battery | Low-flow hand washing, foam cannons | $50–$150 |
| Electric pressure washer | 1,000–2,000 PSI | 1.2–2 GPM | 120V AC | Pre-rinse, wheel cleaning, light decon | $100–$400 |
| Gas pressure washer | 2,000–4,000 PSI | 2–4 GPM | Gas engine | Full pressure washing, fleet, heavy soil | $300–$1,200 |
| 12V high-flow pump + reel | 60–80 PSI | 5–7 GPM | 12V battery | Rinseless wash + foam delivery | $150–$350 |
Complete Rig Equipment List
| Item | Purpose | Amazon |
|---|---|---|
| Poly water tank (35–200 gal) | Water storage | Shop → |
| 12V demand pump (3–5 GPM) | Low-pressure delivery | Shop → |
| Hose reel (retractable, 50 ft) | Organized hose storage | Shop → |
| Battery box + deep-cycle battery | Power for 12V pump | Shop → |
| Tank straps / mounting brackets | Secure tank in truck bed/trailer | Shop → |
| Bulkhead fittings + ball valves | Outlet plumbing | Shop → |
| Pressure washer (electric or gas) | Pre-rinse / heavy cleaning | Shop → |
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Weight and Payload — Don't Ignore This
Water weighs 8.34 lbs per gallon. A 100-gallon tank adds 834 lbs of water weight alone — before the tank itself, pump, hose reel, and equipment. Know your vehicle's payload capacity before sizing your setup:
- Half-ton truck (F-150, Ram 1500, Silverado 1500): 1,500–2,000 lbs payload. A 100-gallon water tank full uses 50–55% of payload. 65 gallons is the practical maximum for a full-tank setup in a half-ton.
- 3/4-ton truck (F-250, Ram 2500): 2,500–3,500 lbs payload. 150–200 gallons is practical.
- 1-ton truck (F-350, Ram 3500): 3,500–5,000+ lbs payload. 250–350 gallons in the bed is workable.
- Enclosed trailer: No payload limit concern for the truck (within towing rating) — tank, pump, and equipment weight counts against trailer tongue weight instead. Use a trailer for 200+ gallon setups.
Use our water weight calculator to calculate exact weight for any tank size.
Water and wastewater treatment professional with 18+ years of hands-on industry experience. Grade IV Wastewater Certification holder. Founded TankAuthority to bring real operator knowledge to water storage decisions.