How Does Houseboat Plumbing Work? | LakeWizard

A houseboat's plumbing is vital to keeping the houseboat functional. It is important to understand how houseboat plumbing works and its basic components.

A standard houseboat plumbing system has the same purpose as a house on land. However, it has its own plumbing and water management system that allows you to access water as needed. If you own a houseboat, it is necessary to understand how the plumbing system works in a houseboat, including its intake and waste output mechanisms. This will help you in the event of an emergency or just if you're looking to perform some routine maintenance.

Houseboats have a pressurized water system that provides water when needed. This system has two water tanks called the gray and black tanks. The gray tank keeps fresh water for usage purposes. In comparison, the black tank holds wastewater from the drains of showers, sinks, dishwashers, etc.

Houseboat plumbing is usually compared to RV plumbing because both are mobilized homes. The plumbing in these accommodations is generally sturdy and long-lasting because they need to withstand the roughness that comes with mobility. But that doesn't mean that houseboat plumbing is unbreakable. You should know how the plumbing and water management systems work on your houseboat, so you have the knowledge to troubleshoot any problems.

As seasoned houseboat enthusiasts, we know all about the different aspects of houseboat plumbing systems. As such, we're in the perfect position to tell you all about the plumbing mechanism that helps you access water for different purposes and how you can troubleshoot the basic problems with houseboat plumbing.

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Houseboat Plumbing System Components

Depending on the size and category of the houseboat, the water is pumped either from the dedicated tank or straight from an external source such as the ocean or the lake. Having two separate tanks for gray and black water also depends on the size of the houseboat. Below are the components that work together to provide you access to the water.


Water tanks are made of rigid polyethylene that can withstand the elements for a long time – they are also incredibly lightweight. The tanks are essentially at the bottom of the boat because the water is heavy. However, that requires more power from the engine, which would be easier if it were at the top. Houseboats usually have space to add more tanks or create divisions between them, depending on the capacity.

Tanks on a houseboat usually have three ports: outlet port, vent hose port, and fill hose port. The outlet port and the vent hose port are generally half-inch wide, while the fill hose port is one-and-a-half-inch wide. The fittings in a polyethylene tank should not be too tight, or they can end up molding the plastic. Instead, use a Teflon tape or a steel hose clamp to secure the fittings.

As mentioned earlier, there can be different tanks in a houseboat. These include:

Fresh Water Tank

The fresh water tank is the base of all your needs when it comes to water on a houseboat as it holds fresh and clean water. Sinks, toilets, showers, filters, and toilets — all of these are supplied from the freshwater tank. As the size of the tank varies from boat to boat, you should be considerate while using the water if you're on the houseboat for longer. If you run out of fresh water, you will need to refill your tank from the marina.

The water that reaches you from the fresh water tank is filtered by its dedicated filter. You can control the water supply from the tank by the control switch. When you turn on the switch, the water pump sucks up the water and directs it to the pipes leading to the outlets. However, it is important to keep the switch off when no water supply is needed to avoid leaks and wastage.

Waste Water Tanks

There needs to be a water-containment system on a houseboat that gathers up all the used water. Fortunately, that place is not the ocean or the lake outside of your houseboat for obvious reasons. Two separate tanks gather the drained water from your sink, toilet, shower, or other sources, even in an average-sized houseboat. The gray tank holds cleaner water drained from hand basins, sinks, and showers. The gray water is inspected for reuse, and if passed, it is treated for certain recycling purposes.

On the other hand, the drainage from the toilets is gathered in the black water tank. You should drain the black water tank every three days to avoid unpleasant odors. You can drain it at the marina, near the waste pumps, or if you're at least three miles offshore, you can dump it there.

Marine Toilets

A marine toilet is similar to regular ones; however, it doesn't have its water-holding tank on the top. The marine toilet consumes water from outside the houseboat, the lake, or the ocean to flush the waste. It has a separate water pump and a filter which causes it to be slightly pricier than the regular ones. However, the wastewater goes to the blackwater tank, the same as regular toilets.


Houseboats have consisted of PVC piping braided with polyethylene for a long time, but the more recent models have the polyethylene tubing (PE), which is more flexible, durable, and cheap. Besides that, the polyethylene tubing offers easy mounting, and the repairing is also convenient. They come in different colors to dedicate different colors to differentiate between the hold and cold supply.

Moreover, the translucent PE pipe is also a healthier choice as you can see through it to notice the algae development. That way, you can change the pipe when needed for the best hygiene practice. The piping you have in your houseboat should be FDA approved, which requires it to be non-toxic, taste-free, and non-contaminating.


Unlike households, pumps are required on a houseboat to supply water to the outlet appliances. There are two kinds of pumps:

Electrical Pump

An electrical pump automatically pumps the water from the tank to the faucets when the water pressure drops below defined measurements. The usual setting is 30 or 40 PSI. A switch will activate when the pump senses the pressure to be below the required pressure, and it keeps the pump on until the tap or other faucets are closed.

Manual Pump

A manual pump requires you to activate and deactivate the pump. It is done through a switch that is generally installed on the helm of the pump. Even though a manual pump requires a bit more effort, it saves a lot more water, which is necessary on a houseboat.


The job of an accumulator in a water tank is to keep the air pressure from building up, which can interrupt the water flow. The accumulator can be big or small. However, this piece of equipment is mounted near the outlet of the water pump so the tank can be filled with maximum capacity. The accumulator can also help you drain a certain amount of water without needing to activate the pump.

Hot Water Supply

The hot water supply on a houseboat is powered by a water heater, a small insulated tank. A water heating system is only possible if you have a pressurized water system, which is the case for most houseboats. The heating system uses a coiled tube or a rod that uses AC power from the generator or an external battery to heat the water.

You don't need an extra pump to drain water from the main tank to the water heater. When you open the hot water tap, the system automatically activates if there is an uninterrupted power supply. However, a valve is generally needed to stop the heated water from falling back into the main tank.

Ensure that all the water heater tank fittings and their outlets are metal. The heat will easily mold plastic, causing leaks and potentially electrical failure.


Faucets are the ultimate appliances to access water from the kitchen sink and hand basins. Houseboat faucets are similar to household faucets, but they may require a different approach for fitting, so make sure they have the right adapters for the plumbing system to work efficiently. You can find different styles of faucets to suit your news best, but a dual connector faucet is necessary if you want hot and cold water to run separately.


A shower is another basic amenity on a houseboat, and they have a similar connection to a faucet. While a faucet connection is directly through a stopper, a shower is supplied with water from the insulated PVC or PE fitting.

Showerheads are also available in plastic, but they wear out quickly if you use heated water mostly. So it's best to use a metal showerhead.


The drains on houseboats can consist of various materials. The sink drain is typically a rubber hose that leads to the gray water tank. On the other hand, the shower and hand basin drains use a bilge pump to pump the water out from the drain because they are generally beneath them overboard.

Ensure that no bunches of hair get stuck in the drainage system, causing an unpleasant smell and requiring maintenance. The toilet drain leads directly to the black water tank, and there is little room for anything to go wrong.


Washdown pumps are an exclusive feature that only the big houseboats can afford. The washdown pumps supply water to wash down the deck. Since most average-sized boats only carry enough water for necessities, a washdown pump is a luxury they can't afford.

However, you can get a washdown pump separately for your houseboat and connect it to a faucet on the deck for water supply.

A washdown pump can be connected to the faucet via a rubber hose or a PE tube. However, if debris enters the washdown pump, it can block it and cause invented pressure. Therefore, ensure the water supply hose and faucet's attachment are reinforced with a tee-connector or a Y-connector.

Convert Seawater to Fresh Water

Treating seawater for commercial and residential use is becoming a norm on a broad scale. However, you can also use seawater on your houseboat, so you don't have to head back to the marina every time your freshwater tank empties. The process of converting seawater into freshwater is known as desalination.

The process involves a desalination system that drains water from the sea and is run through a reverse osmosis membrane in a pressurized manner. This separates the contaminated water and the impurities, and the treated water is pumped into the water tank. The remains are drained out back in the sea, giving you an uninterrupted freshwater supply.

The desalination process removes 99% of the salt, impurities, microorganisms, and uncomposted elements.

Maintaining the plumbing system is important for the fine experience you are looking for on a houseboat. Therefore, when looking for a houseboat, consider the plumbing system on the houseboat and how its freshwater supply will keep your needs satisfied for the maximum amount of time. After all, water is a necessity on the houseboat – as vital as any other place.