Black Tank Care Without the Horror Story

Please note: general information from our own experience, not professional advice. Follow your manufacturer's instructions, and for work involving electricity, propane, or safety systems, use a qualified RV technician or licensed electrician.

The least glamorous system on the rig

Every RVer has a black tank story, and most of them start with the same mistake. Here is the plain version of black tank care, the way it was explained to us after we needed to hear it.

Water is your friend

The black tank works when there is plenty of water in it. Start each use with several gallons of water in the tank, use generous water with every flush, and treat a dry tank as the enemy. Solids in a low-water tank do not break down or flow out; they settle, harden, and build.

Never leave the black valve open

Hooked up at a site, it is tempting to leave the black tank valve open so the tank "drains itself." Do not. The liquids run out and the solids stay, layer on layer, into the plug every RVer dreads. Keep the black valve closed until the tank is at least two-thirds full, then dump. Let the gray tank fill too, and dump it after the black: the gray water rinses your hose.

Treatments and paper

Enzyme or bacterial treatments help break down waste and control odor; harsh chemicals are hard on seals and on dump stations. Use RV or septic-safe paper, which breaks down fast, and test any new paper in a jar of water: shake it, and see if it falls apart.

Dumping, decently

Gloves on. Secure connections before any valve opens. Rinse the tank with a flush inlet or wand if your rig has one, rinse the hose, and leave the dump station cleaner than you found it. Somewhere in our sample-trip ledger, dump fees on that trip went unrecorded, marked UNKNOWN in the report. Even the unglamorous lines deserve counting.

Related: how we keep the trip ledger.