How much RV antifreeze do I need — and what’s the right order?

Pick your RV class and method. You’ll get the gallons of antifreeze to buy and a printable, step-by-step checklist tailored to your rig — including the water pump, black-tank flush line, and city-water inlet check valve that most online guides skip and that crack hardware every winter.

RV class

Method

Which should I pick?

Blow-out alone can leave residual water pooled in low spots, valves, and the pump — in hard-freeze climates, “Both” is the safest. Note: Keystone’s “4–6 gal” figure is for their fresh-tank-pour variant, so it isn’t comparable to this tool’s pump-direct numbers.

Water heater

Water-heater bypass

Extra fixtures (faucets/sinks/showers beyond galley + 1 bath)

P-traps + toilet (defaults to your class)

Features on your rig

What this tool does and doesn’t do.

It sizes the quantity of antifreeze and orders the steps. It does not guarantee freeze protection to any temperature — burst-point ratings vary by brand and dilution. Check your antifreeze label’s rated temperature.
Use RV/marine non-toxic (propylene-glycol) antifreeze only. Never use automotive/engine antifreeze — it’s toxic.
For appliance-specific steps (residential fridge, dishwasher, washer, tankless/on-demand heaters, hydronic heat like Aqua-Hot, specific icemaker models), follow your owner’s manual — this tool only flags that they need attention.
Estimates round up and include a ½-gallon buffer — treat the number as “buy at least this many.”

Stock up

You’ll need RV/marine non-toxic antifreeze (the pink stuff) and, if you’re going the air route, a blow-out adapter. Search RV antifreeze on Amazon.

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Methodology & sources

The gallon estimate starts from a per-class base for the pump-through method with the water heater bypassed, then adds small amounts for extra fixtures and appliances, plus one quart per P-trap and two quarts for the toilet, and a half-gallon buffer (antifreeze is sold by the jug). The single biggest variable is the water-heater bypass: skipping it on a tank heater adds 6 or 10 gallons. The air method uses no bulk antifreeze — only the P-trap/toilet reserve.

The checklist order and the freeze-critical steps (clearing the water pump on the air method, the black-tank flush line, and the city-water inlet check valve on the pump method) follow the manufacturer and retailer guides below. Every number is drawn from these sources.

Tool data REV . Refreshed seasonally against the sources above.