RV Fresh Water System

The typical RV fresh water system is a combination of advanced technical accomplishment balanced by the economic principles of profit and loss. The manufacturer desires a functional water supply system at a "cost-effective" level, and generally this is the case.

Modern RVs are equipped with 12-volt automatic pressure demand water pumps, polyethylene fresh water storage tanks, and PEX or polybutylene water lines. The various joints and connections are typically compression or crimp-ring fittings, which are quick and economical to assemble at the factory level when everything is exposed.

These systems are designed to operate at a maximum water pressure level in the range of 35 to 45 PSI. The onboard pump has a built-in pressure switch that shuts off power to the pump when this pressure is reached.

However, when connecting to a city water supply at a campground or home, water main pressure can frequently exceed 80 to 100+ PSI. This high pressure can easily rupture PEX fittings or blow water lines off their barb connections, creating severe interior flooding.

A water pressure regulator is essential whenever connecting to an outside municipal water source. This device controls incoming water pressure to supply a safe, continuous 40 to 50 PSI maximum. Always attach the regulator directly to the campground spigot to protect both your drinking water hose and the RV plumbing lines.

Plumbing Guides & Resources

• RV Holding Tanks

  Managing black and grey waste tanks, choosing treatments, and maintaining dump valves.

• Holding Tank Sensors

  Troubleshooting false monitor panel readings and cleaning fouled tank probes.

• RV Waste Valves

  Servicing, lubricating, and replacing 3-inch black and 1.5-inch grey waste gate valves.

• Grey Water Transfer System

  Plans for a homemade grey water transfer system using a 3-way diverter valve.

• RV Winterizing

  Step-by-step procedures for winterizing water lines using RV antifreeze or air blowout methods.

• RV Dewinterizing

  Spring startup guide for flushing antifreeze, sanitizing tanks, and restoring water systems.

• Dometic Sealand RV Toilet Repair

  Replacing ball seals, water valves, and spring cartridges on Dometic pedal-flush toilets.

• Water Pump Noise

  Soothing 12V water pump chatter, pipe vibration, and PEX line hammering.

• Squeaky Taps

  Fixing RV faucets and taps that squeak or squeal when turned.

• Homemade Sewer Hose Holder

  DIY PVC bumper-mounted sewer hose carrier build plans.