Water in the RV: usage, tanks, hygiene and winter operation
Water in an RV is comfort, payload and a hygiene question all at once. If you know your usage, you drive lighter, boondock longer and dump less often. This article sums up the basics.
How much water do you need per day?
At home a person uses around 80 gallons (300 L) a day. In an RV it's 2.5 to 10 gallons (10–40 L) depending on habits: drinking and cooking 0.8–1.3 gal (3–5 L), dishes 1–2.6 gal (4–10 L), hygiene 0.5–1.3 gal (2–5 L), toilet flushing 0.3–0.8 gal (1–3 L) and – the biggest item – showers at 2.6–10 gal (10–40 L) per shower.
| Style | per person and day | 2 people, 26 gal (100 L) tank |
|---|---|---|
| Frugal (shower at the campground) | ≈ 3 gal (12 L) | ≈ 4 days |
| Normal (shower every 2nd day) | ≈ 6.6 gal (25 L) | ≈ 2 days |
| Comfortable (daily shower) | ≈ 10.5 gal (40 L) | ≈ 1.2 days |
Fresh and gray water tanks
The gray tank is often smaller than the fresh tank – and it takes 80–90% of the water used. In practice you therefore often have to dump before the fresh water is gone. Gray water belongs exclusively in dump stations; dumping it on the ground is prohibited.
For driving: as little water as necessary. 26 gallons (100 L) is 220 lb (100 kg) of payload, possibly behind the rear axle. Many drive with 5–10 gallons (20–40 L) and fill up at the destination.
Hygiene: keeping tank and lines clean
- Use only drinking-water-safe hoses and don't lay them on the ground.
- Don't leave water in the tank for weeks; drain tank and water heater before longer periods of storage.
- Sanitize the tank regularly (e.g. with a diluted bleach solution per the manufacturer's instructions, then flush thoroughly).
- Drinking water from the tank is possible if the system is clean – many still use bottled water or a filter.
Hot water
A 2.6 gal (10 L) water heater at 140 °F (60 °C) mixed gives about 4.9 gal (18 L) of shower water – about three to four minutes at 1.3 gal/min (5 L/min). The trick: turn the water off while soaping. Heating it up costs about 0.5 kWh, i.e. about 1.8 oz (50 g) of propane. Typical US RV tank heaters hold 6 or 10 gallons and last correspondingly longer.
Winter operation
- Heated tanks and underbelly only protect while the furnace runs – keep it on in freezing weather or winterize.
- Run the gray tank with a little RV antifreeze or with the dump valve open into a bucket in freezing weather.
- Drain water lines in unheated areas (outdoor shower, exterior compartments).
- Drain the fresh water hose after filling – otherwise it freezes to the ground.
Published 09/19/2026.