How to Use a Pump-Out Station: Finding One, Hooking Up and Rinsing the Tank

Pump-outs are at many marinas, fuel docks, public docks and some ramps. A few ways to find one:

• Your state's Clean Vessel Act program. The US Fish and Wildlife Service's Clean Vessel Act program gives grants to state boating agencies to build and run pump-out stations and to tell boaters where they are. Most state boating agencies list or map their stations.
• EPA's NDZ page. The EPA's no-discharge-zone page by state links to many state pump-out and clean boating pages, and has a map of current NDZs.
• Apps. Pumpout Nav is a free app that shows the nearest stations, whether they are working, hours and cost. It was built by the San Francisco Estuary Partnership with Clean Vessel Act money and now covers several areas beyond California, such as Lake Champlain. Coverage varies, so check your area.
• Your marina office or harbormaster. They know which stations are working this week.

Pump out before the tank is full, not after. An overfilled tank can push waste and paper into the pump-out hose and vent line and clog them. On summer weekends the pump-out dock can have a line, so go early or mid-week when you can.

Come alongside, tie up bow and stern, and shut off the engine if you will be there more than a minute or two. Leave room for the next boat. Read the instructions posted on the station; BoatUS notes that most stations have them, and machines differ.

Open the waste cap with the deck key and set it somewhere it cannot roll overboard. Double-check that it is the waste fitting. Look at the O-ring on the cap; if it is cracked, replace it so the cap seals and does not let odor or water in.

Make sure the valve on the pump-out nozzle is closed, then check that the rubber tip fits your deck fitting. BoatUS says that if it does not, you may need an adapter, which stations often have. Some boats carry their own adapter to be safe.

Start the station (usually a button or switch), let it build suction, then press the nozzle firmly into the fitting and slowly open the valve. If the hose has a sight glass, you will see waste moving; if not, listen for the change in sound when the tank empties.

When the tank is empty, BoatUS suggests flushing some fresh water through the head and pumping that out too. Many owners repeat this a couple of times to rinse solids off the tank bottom and the sensor. Some stations have a rinse hose for this; never put a potable water hose into the waste fitting, and never use the station's rinse hose to fill your drinking water tank.

Keep the pump running for a few seconds after the tank is empty so the hose clears, then close the nozzle valve and remove it. If the station has a bucket of clean water or disinfectant, BoatUS describes drawing a little through the nozzle and closing it again, without letting it drip into the water.

Put the cap back on your fitting and tighten it. Coil the hose the way you found it, turn the pump off if it has a switch (some run on a timer and shut off by themselves), and wipe up any drips. Put used gloves and paper towels in the trash, not in the water.

BoatUS says a machine that runs but has little suction usually has lost its prime or has a worn diaphragm. Report it to the marina or the app and go to another station. Do not try to repair it yourself.

The problem is likely on your boat:

• Clogged pump-out hose. BoatUS says this often happens after overfilling or when the boat heels and sloshes waste into the hose. A plumber's snake down from the deck fitting can clear it.
• Clogged vent. If air cannot get into the tank, the station cannot pull waste out, and BoatUS warns the tank can even collapse under vacuum. Check the vent fitting on the hull for a blocked or corroded screen. See holding tank vent filter.
• Tank refills while pumping. BoatUS says this almost always means the overboard seacock at the end of the macerator line is open, letting seawater flow back in. Close it.

Many harbors have pump-out boats that come to you, often on a schedule or by call or VHF. Ask the harbormaster how to request one and whether there is a fee. Have your deck fitting open (or the key ready) and keep the boat steady while they work.

Regular pump-outs, good hoses and a working vent keep odors down. BoatUS notes that old sanitation hoses let odor pass through them, and that household cleaners can stop holding-tank treatments from working. See holding tank deep clean and sanitation hose descaling.