RV frozen or cracked water line: what to check and what it costs

A cracked water line, a split pump housing, or a ruptured fitting is the single most common thing we find on the first RV plumbing call of spring in the Prescott area, and the cause is almost always the same: water left in the system through a hard freeze. Water expands by roughly nine percent when it turns to ice, and that expansion is more than enough to split copper, PEX, and plastic fittings wherever it got trapped. Prescott’s own climate record shows about 128 nights a year at or below 32 degrees, so the exposure here is real, not occasional.

Check this first (ten minutes, before you pressurize)

Look before you turn anything on. Check under the rig, inside the plumbing bay, and in cabinets around the water pump and water heater for staining, dampness, or ice that has not fully melted.
Pressurize slowly. Turn the pump or city water inlet on gradually rather than all at once, and stay near the rig while pressure builds.
Listen. A hiss, a running-water sound with no fixture open, or the pump cycling nonstop without reaching pressure all point to a leak somewhere in the system.
Check the water heater specifically. A tank that was not bypassed and drained is a common freeze casualty, and a cracked tank can leak slowly enough to go unnoticed for a while.
Open each fixture in turn and note anything unusual: reduced flow, air sputtering that does not clear, or water where you do not expect it.
If you find one leak, keep looking. A hard freeze that cracked one fitting very often cracked another. Fixing the first one you find and calling it done is how a second leak shows up a week later.

What is usually wrong

What you find	Likely cause	Fix and cost
Spray or drip from a line inside a cabinet on first pressurization	Cracked PEX or fitting from freeze expansion	$150 to $350
Pump runs constantly, pressure never builds	Leak downstream, or an empty tank	Diagnose first, then $150 to $350 typical
Water pooling under the water heater	Cracked tank from an incomplete winterization	$700 to $1,800 replacement
Multiple small leaks found on a full pressure test	Several fittings hit by the same hard freeze	$400 to $900
No visible leak but low pressure at every fixture	Airlock or a partially blocked line, not freeze damage	Diagnose first, often a smaller fix
Leak only near an ice-maker or outside shower line	Low-point line often missed in a rushed winterization	$150 to $350

These sit inside the plumbing repair range on the pricing page, on top of the $75 to $150 trip fee and $125 to $190 hourly labor.

Why this is a Prescott problem more than a desert one

Water freezes at 32 degrees regardless of location, but how often a Prescott-area RV actually sees that temperature is the difference. Prescott’s climate record shows an average of roughly 128 days a year with a minimum temperature at or below freezing, January lows averaging in the mid-20s, and a record low of -21 set in 1937. A rig in the low desert two hours south rarely needs to think about this at all. A rig here, whether parked at a campground, a storage yard, or on rural acreage, has real exposure across an entire winter, and the risk is not a single unlucky cold snap, it is the accumulation of many freezing nights in a row.

The rigs most at risk are the ones with a partial winterization: tanks drained but the water heater left full, or antifreeze pushed through the main lines but not the low-point drains, the outside shower, or an ice-maker line. Any water left standing anywhere in the system through even one hard freeze is a crack waiting to happen, and it often does not show itself until the system is pressurized again, sometimes weeks or months later.

Preventing it going forward

A full winterization before the first hard freeze is the fix, not a partial one. That means draining fresh, gray, and black tanks, bypassing and draining the water heater specifically, and blowing out or antifreezing every line, including the ones that are easy to forget. Our maintenance and winterization service covers exactly what that includes, and the winterizing blog post walks through the seasonal timing.

If the rig is going to stay hooked up and used through winter instead, heated skirting and heat tape on exposed lines are the alternative, but that setup has to hold through every cold night, not most of them; a single power outage on a heated-but-not-winterized rig during a hard freeze can produce the exact same damage.

What to expect on the call

Tell us whether you have found one leak or several, whether the rig was winterized last fall and how thoroughly, and how long it sat unheated. We pressure-test the entire system rather than stopping at the first crack, because a hard freeze rarely damages just one spot. We work on site across Prescott, Prescott Valley, Chino Valley, Dewey-Humboldt, Williamson Valley, Paulden, and Mayer, and the plumbing repair and water pump pages cover the rest of the system in more depth.

Frequently Asked Questions

How do I know if a freeze cracked my RV plumbing?

The clearest sign is water spraying, dripping, or pooling somewhere it should not the first time you pressurize the system after winter, often from inside a cabinet, under a sink, or in the underbelly. A quieter sign is a water pump that runs constantly and never builds pressure, which usually means it is pushing water out through a crack you have not spotted yet.

What does it cost to fix freeze damage?

A single found crack or fitting runs $150 to $350. Because a hard freeze rarely damages just one spot, we pressure-test the whole system rather than stopping at the first leak, and multi-point freeze repair typically runs $400 to $900. A cracked water heater tank is $700 to $1,800 to replace.

My rig was 'winterized' last fall. How did this still happen?

A partial winterization is the most common cause: tanks drained but the water heater not bypassed and drained, or antifreeze pushed through some lines but not the low-point drains or an ice-maker line. Any water left standing anywhere in the system is a crack waiting for the next hard freeze.

Is it safe to just turn the water on and see what happens?

No. Pressurizing a system with an undetected crack can spray water into cabinets, walls, or the subfloor before you notice, and that kind of hidden water damage costs far more than the plumbing repair itself. Pressurize slowly, watch and listen, and stop the moment anything looks or sounds wrong.