Three tanks, three jobs. Understand the flow and the dreaded parts of RV plumbing turn into a five-minute routine.
Fresh water
Two ways to get water: fill the fresh tank and run the 12V pump, or connect city water at a campground. Two rules: always use a drinking-water-rated hose (usually white or blue), and always use a pressure regulator on city water — park plumbing can run high enough to burst RV lines. Sanitize the fresh tank at the start of each season with a diluted bleach solution flushed through every tap.
Grey water
Sink and shower drainage. It fills faster than you expect — dishes are the culprit. At a full-hookup site, keep the grey valve closed and dump when it is over half full; leaving it open lets odors migrate and traps grease along the pipe. Off-grid, grey capacity is usually what ends the trip, so navy showers and a dish tub stretch it.
Black water
The toilet tank. The routine that prevents 95% of problems:
- Keep the black valve closeded at all times until dumping — dumping a tank that is at least two-thirds full lets the volume carry solids out.
- Dump black first, then grey, so the grey water rinses the hose.
- Use plenty of water with every flush and a tank treatment you like; “dry” tanks build the pyramid nobody talks about at parties.
- Rinse the tank (built-in flush or a wand) every few dumps.
The kit to carry
Drinking-water hose, pressure regulator, sewer hose with clear elbow (you want to see when it runs clear), disposable gloves, and a separate rinse hose that never touches the fresh side. Label them; never cross them.
Before your next trip: run the free 47-item pre-trip checklist. Gearing up? The Camp-Ready Gear Guide ($17) covers 50 picks by budget tier, and the RV Life Launchpad course ($97) walks the whole system from rig choice to life on the road.