Macerator Pump
A pump system that grinds black-tank solids and pumps waste through a 1-inch hose, allowing dumping at sewer cleanouts not accessible to a gravity-fed RV drain.
Also called: macerator, macerator pump, grinder pump
A macerator pump is a pump system mounted on an RV’s black tank that grinds solids and pumps waste through a 1-inch hose, rather than letting it flow by gravity through a 3-inch dump station connection.
Why macerator pumps exist
Three use cases:
- Dumping at sewer cleanouts that are higher than the RV’s drain (you can’t gravity-dump uphill)
- Long-distance dumping at sites where the dump station is far from RV parking
- Private sewer connection in residential settings (an RV in someone’s driveway connecting to a house sewer cleanout)
How the procedure differs
Standard gravity dump: open the gate valve, gravity moves waste through the 3-inch hose.
Macerator dump: attach the smaller 1-inch hose, turn on the macerator pump, the pump grinds and pumps waste through the smaller hose.
When you’ll encounter one in a rental
Most rental RVs use gravity drainage and don’t have macerator pumps. Exceptions:
- Some luxury Class A diesel pushers
- Some fifth wheels designed for residential use
- A few specialty rental fleets
If your rental has one, the operator will demonstrate it at pickup. Don’t operate without the walkthrough — the failure mode (clogged macerator) is unpleasant.
What macerators don’t do
A macerator pump doesn’t eliminate the dump-station visit; it just moves waste through a smaller hose. You still need to find somewhere to legally dump.