Water Lines Freezing

[Twisties]

So, the hot water line to the kitchen sink has frozen three times now. Once when we had a low of 15 F, once when we had a low of 14 F, and last night with a low of 10 F. Last night, the cold water line froze as well.

We are filling the fresh water tank and running off the pump, to avoid freezing our water hose. The water pump is not running without demand, therefore we believe there has been no damage, or at least no leaks.

The 10 F was surprise, and a record low for the date and area. We don't expect to see that again, but we need to figure out how to handle 15 F, as we may come close to that again.

We had the tank heating pads running, we had turned off the electric space heater so the propane central heat ran more, left the thermostat up at night, and opened the cabinet doors... still froze up.

The lines originate in an area behind the pass through compartment which houses the pump, water heater and propane furnace. We don't see any evidence of freezing in that area, as all the other water works, and it's all right there.

The kitchen lines meet up in that area and then dive into the underbelly where we can't see them. They come back up about 5-6' away in the far end of the kitchen island, behind the drawers.

Questions: If this continues is it likely to cause damage, or is this ok? If we want to have this fixed, is it a warranty issue (we're supposedly 0 F rated)? If not, or if we don't want to take the trailer back to Oregon (we're in New Mexico and headed east), what would we do about it?

Thanks!