Fill an RV fresh water tank through the gravity fill inlet, or through the city water inlet if your water panel has a tank fill setting, using a hose sold for drinking water. Sanitize it with household bleach, let the solution stand, then flush until the chlorine smell is gone.
How to Fill, Sanitize and Clean an RV Fresh Water Tank
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At a glance
- Bleach amount: 1/4 cup of household bleach in one gallon of water, one gallon of solution per 15 gallons of tank capacity, the mix Jayco, Keystone, Forest River, Grand Design and Winnebago all print.
- Standing time: builders differ, from 3 hours to at least 24 hours, so follow the manual for your own camper.
- Traveling full: water weighs about 8.3 lb per gallon and counts against the trailer's cargo carrying capacity.
On this page (5)
How do I fill the fresh water tank?
Which fill point you use depends on your camper, and neither one shuts off on its own. The gravity fill is a capped inlet on the sidewall that you pour into. The city water inlet feeds the plumbing directly and only fills the tank if a panel valve is set to tank fill.
Use a non-toxic drinking water hose kept only for fresh water, with the hose ends off the ground, as Jayco's 2027 towable manual instructs. On city water, Keystone says to always use a water pressure regulator.
Gravity fill:
- Close the low point drains and the fresh water tank drain.
- Remove the fill cap and put the hose or a funnel into the inlet.
- Fill while watching the monitor panel, and turn the source off when the tank is full.
- Replace the cap.
Tank fill through the city inlet, from Winnebago's 2026 towables manual: connect the hose at the docking station, turn the selector valve to tank fill, leave the water pump off and turn the water on. Set the valve back to system use when the tank is full.
Stay with the tank while it fills. An overfilled gravity tank spits water back out, and Keystone warns that overfilling can damage system components.
Tip: Before you hook up at a campground, the CDC says to confirm with the manager that the water is safe to drink. If you are dry camping, fill from a known drinking water source such as a home tap.
How do I sanitize it, and how much bleach?
All five builders on this page use the same mix: 1/4 cup of household bleach (5 percent sodium hypochlorite) in one gallon of water, with one gallon of solution for every 15 gallons of tank capacity. Keystone's example is 2 3/4 gallons of solution for a 40-gallon tank, with half the bleach if you use an Ultra concentrate. Your tank capacity is in your owner's manual.
Jayco's steps:
- Turn the water heater off, both the electric and gas switches.
- Set the water heater bypass valves to bypass, if your heater has a tank.
- Level the RV and drain the fresh water system.
- Close the low point drains and the tank drain, and reinstall the water heater drain plug.
- Remove the cartridge water filter from its housing, because a canister filter has no bypass.
- Pour the solution into the tank through the gravity fill inlet.
- Fill the tank with potable water.
- Turn the pump on and open the hot faucets until the water smells of chlorine, then repeat with the cold faucets, the outside shower and the toilet.
- Close the faucets, turn the pump off and let the solution stand.
- Drain, refill with potable water, and run every faucet until the chlorine smell is gone. Repeat if it lingers.
| Builder | Standing time | Bypass the water heater |
|---|---|---|
| Jayco | At least 4 hours | Yes, before adding solution |
| Keystone | 4 hours | Not in its sanitizing steps |
| Forest River | At least 3 hours | Not in its sanitizing steps |
| Grand Design | 3 hours | Not in its sanitizing steps |
| Winnebago | At least 24 hours | Yes, same valves used for winterizing |
Times from the Jayco 2027 towable, Keystone 2027, Forest River travel trailer and fifth wheel, Grand Design Momentum and Winnebago 2026 towables manuals.
Jayco also offers a stronger mix, 1/2 cup of bleach per gallon, which stands one hour instead of four. If a chlorine taste remains after the flush, Jayco and Grand Design run one quart of vinegar to five gallons of water through the system as a rinse.
Sanitize a new RV, at the start and end of each season, after storage and whenever you suspect contamination. Jayco adds every three months of use.
Tip: A Keystone power fill model has no gravity port, so pour the solution in through the arched tank vent on the sidewall with a funnel and tube, then refit the vent cover and bug screen. Grand Design instead draws the solution in through the city water connection with the pump, using a short hose that is not your drinking water hose.
Draining and cleaning the tank after storage
After storage, drain whatever is left before you sanitize and refill. The tank empties through a valve near the tank, often a white T-handle or a plastic drain under the skirting. The lines empty through the low point drains under the floor near the tank.
Open the faucets so air can get in, keep the water pump off while draining, and pull the water heater drain plug if you are emptying the whole system.
No builder gives a scrubbing step or endorses a tank cleaner: the bleach cycle above is the cleaning.
Tip: A rotten egg smell from the hot water needs a different dose. Suburban's water heater guide calls for about six ounces of bleach per 10 gallons in the tank, left for a few days, then flushed out. Do not use that amount as your sanitizing mix.
Should I travel with the tank full?
Usually not: water is cargo, and Jayco's yellow capacity label does not include the weight of a full fresh tank. Grand Design puts water at 8.3 to 8.34 lb per gallon, so 50 gallons is 417 lb by its own arithmetic.
Jayco warns that full tanks may exceed the tire ratings, the axle rating or the trailer's GVWR and affect handling. Jayco and Forest River say to travel dry or near dry and fill at or near the destination, or not at all if the site has pressurized water.
Common questions
Should I empty the fresh water tank between trips?
Yes. Jayco says to drain any unused water from the fresh water system at the end of every trip, and Keystone says to drain it whenever the system is not in use.
How long can water sit in an RV fresh water tank?
There is no set number of days: Keystone says water quality degrades over time, so drain rather than store it. The CDC's RV water fact sheet says most RV makers recommend draining, disinfecting and flushing at least once a year, or after the RV has sat unused for a few months.
Is it really necessary to sanitize the water system?
Yes. The CDC says germs can grow in any water system, RVs included, and that tap water is not sterile. Keystone and Winnebago both say to sanitize, flush and drain the tank before using it.
Can I use vinegar instead of bleach?
Only if the solution is hot. Jayco says a 50/50 white vinegar and water mix sanitizes only at 130°F (54°C) or above, a temperature the RV water heater will not reach. Unheated vinegar cleans and descales but does not sanitize.