Freshwater Holding Tank
A bathroom on a houseboat looks similar to a regular house bathroom. The difference is that a houseboat has its own water and sewage system. The sink and shower in a houseboat bathroom gets water from the onboard freshwater holding tank. The freshwater holding tank has a water hose connection that can be reached from the outside of the boat. At that connection, the tank can be filled with water. To fill the tank, one end of a hose is fitted onto the tank connector and the other end of the hose is attached to a city water source at a harbor. When a houseboat is parked for a long length of time, it can stay hooked up to a water hose, for an unlimited source of water.
Sewage Holding Tanks
The sewage on a houseboat empties into holding tanks that are located on the boat. The sink and shower empty into a gray-water holding tank. The toilet empties into a black-water holding tank. Holding tank treatment chemicals are put into the holding tanks through the sink and toilet to prevent bad odors. Holding tanks can be emptied at a harbor or at sea. To empty a holding tank at a harbor, one end of a sewer hose is connected to the holding tank. The other end of the sewer hose is connected to the harbor sewage system. The valve on the tank is opened, allowing the sewage to empty. Boats that are equipped to empty sewage out at sea have a button located inside the boat that opens the tanks. Each country has different regulations that stipulate how far a boat must be from shore before it can empty its sewage in the water.
Other Types of Toilets
Some houseboats have been-fitted with alternate types of toilets, to eliminate the need for a black water tank. The two main types of toilets that do not require a black-water tank are composting toilets and incinerator toilets. Marine composting toilets work the same way as house composting toilets do. The only difference is that marine composting toilets are made smaller so that they can fit in a smaller space. Composting toilets use little to no water to operate. Dirt and a substrate such as sawdust is kept inside the composting toilet. Waste mixes with the dirt and substrate and biodegrades into compost. Incinerator toilets are made out of steel. They actually burn the toilet paper and waste.
Houseboat bathrooms require a couple of special considerations. Nothing should be put into the toilet except urine, feces and toilet paper. Other items can clog the plumbing in the sewage system. The gray-water and black-water tanks must be emptied regularly for both odor control and to empty them when they are full. In hotter weather, the tanks need to be emptied more often, because the hot weather makes odors develop faster. If the tanks are not emptied when they are full, they leak, causing an unsanitary mess. When a houseboat is not hooked up to a permanent water supply at a harbor, water must be used wisely. Houseboats come with different size freshwater holding tanks, but no matter how big the holding tank is, the waster supply is limited. On a long trip, water should be used sparingly to make the supply last. Gauges on the boat show how full the freshwater, gray-water and black-water tanks are.