Boat Plumbing Systems Explained: Marine Faucets, Toilets, Hose & Washdown Pumps

Let's Be Honest: Nobody Thinks About Plumbing Until It Breaks

You're out on the water, everything's perfect, and then the head starts smelling like low tide in July. Or the galley faucet drips every time the boat rocks. Or you pull the anchor, and it comes up buried in a mountain of slimy mud with no way to rinse it off.

Sound familiar? Most boaters have been there.

The good news is that boat plumbing problems are rarely a mystery once you understand how the system works. And fixing them, or avoiding them altogether, usually comes down to having the right parts in the right places.

This guide walks you through four components that sit at the heart of every boat plumbing system: marine faucets, marine toilets, marine hoses, and washdown pumps. We'll explain what each one does, what to look for when you're buying, and how to make sure everything works together the way it should.

How a Boat's Plumbing System Actually Works

Think of your boat's plumbing in four simple layers. Clean freshwater comes in from an onboard tank and flows through a pump to your faucets, galley, and shower. Used water drains away through properly sealed through-hull fittings. Toilet waste goes into a holding tank and gets pumped out at a marina, not overboard. And a washdown pump pulls seawater from outside the hull to rinse down the deck on demand.

It's not complicated, but it is very different from plumbing ashore. At home, you've got a water supply, a sewer connection, and gravity doing most of the heavy lifting. On a boat, you're working with finite tank water, overboard drainage, Coast Guard sanitation rules, and components that have to survive saltwater, vibration, and constant exposure to the elements.

That's exactly why marine-grade components matter. A standard tap from the hardware store might last 20 years in your kitchen. Bolt that same faucet onto a boat, and you'll likely be replacing it within a season. Marine faucets, marine hose, and marine pumps are built differently, from the inside out.

What Is a Marine Faucet and How Is It Different From a Household Faucet?

A marine faucet is probably the most touched piece of plumbing on your boat. You use it to fill a kettle, rinse your hands, wash produce, and top up the water dish for your dog when you're anchored out. Which is exactly why it's worth getting right.

What Makes a Marine Faucet Different?

The difference isn't just branding. Marine faucets are made from materials that can actually handle what life aboard throws at them. Inside, that means brass bodies that won't corrode when they're constantly exposed to moisture. Outside, that means chrome or brushed stainless finishes that won't pit and stain in a salty, humid environment.

Put a standard residential faucet in the same conditions, and you'll start seeing corrosion at the base within a season. It's not a quality issue; it's simply the wrong tool for the job.

The Four Types You'll Come Across

• Galley faucets are the main kitchen sink faucets on a boat. Basic systems use cold-only single-lever models, while boats with water heaters use hot and cold versions. A high-arc spout makes washing larger pots much easier, especially on longer trips.

• Combination sink and shower faucets are ideal for small heads. One unit serves both the sink and a handheld shower, with a diverter to switch between them, a practical space-saving solution for compact boats.

• Transom or deck shower faucets are installed outside, usually near the stern. They’re used to rinse off after swimming or fishing. Because they’re exposed to sun and saltwater, corrosion-resistant materials like 316 stainless steel are strongly recommended.

• Manual pump faucets operate without electricity. You pump a handle to draw water from the tank. They’re simple, reliable, and popular on smaller boats or sailboats where reducing electrical load matters.

What to Look for Before You Buy

Material first, always. For anything inside the boat,  galley, head, chrome-plated brass is the standard, and it's fine. For anything on deck or exposed to direct saltwater, only stainless steel will hold up long-term. Avoid chrome over zinc (pot metal). It looks identical in a catalogue photo and fails noticeably faster in real conditions.

Then check your system type. If your boat has an electric pressure pump, your faucet just needs to open and close,  exactly like one at home. If you're running a manual hand-pump system, you need a faucet built for that flow. Getting this wrong is the most common installation mistake.

Well-regarded brands in this space include Sea-Dog, Whale Water Systems, Fynspray, and Scandvik, all of which you'll find at Go2Marine.

How Does a Marine Toilet (Boat Head) Work?

Sailors and powerboaters alike call it the head, a name that dates back centuries, when the open bow (or 'head') of the ship served as the crew's toilet. The name stuck. The technology has improved somewhat since then.

If there's one part of your boat's plumbing system worth fully understanding, it's this one. Because, unlike a dripping faucet, getting your sanitation system wrong has legal consequences, not just inconvenient ones.

How a Marine Toilet Works

A marine head doesn't rely on gravity and a sewer connection the way a land toilet does. Instead, it uses either a hand-operated pump or an electric motor to do two things: pull seawater in through a dedicated through-hull fitting to flush the bowl, and push waste out through the discharge hose into a holding tank.

That holding tank is where the waste stays until you reach a marina pumpout station. From there, it's handled properly, ashore. Simple in principle, but important to get right in practice.

Manual, Electric, or Portable: Which Do You Need?

• Manual heads use a hand pump to control everything. They're mechanically simple, they don't need any wiring, and they're easy to service at sea.
  

  

  
  

• Electric heads automate the flush cycle with a 12V or 24V motor. Most include a macerator, a grinding mechanism that breaks up solid waste before it's pumped through the discharge hose. This reduces clogging and allows for longer or narrower hose runs.

  

  
  

• Portable and composting toilets are a practical choice for smaller day boats, trailer boats, or any vessel where installing fixed plumbing isn't feasible.  They produce no liquid discharge and create far less maintenance overhead once you get the hang of them.

Choosing the Right Head for Your Boat

For most boats in the 20-40 foot range, a 12V electric toilet from Jabsco or Dometic hits the sweet spot of comfort and simplicity. If you're on a smaller vessel and want zero electrical complexity, the Johnson Pump AquaT manual head is hard to beat. Find these on Go2Marine

Marine Hose: The Part Everyone Forgets Until It Smells

That stubborn, bad smell inside the cabin is often caused by old or low-quality plumbing hoses. Over time, some hoses absorb waste and let odours seep through, even if everything looks clean.

Hoses don’t get much attention, but they play a major role in your boat’s plumbing system, and when they fail, they can create some of the most frustrating problems onboard. Here’s what you should know.

Not All Hose Is the Same

There are three main types of marine hose, and each one has a job it's built for. Using the wrong type is one of the most common plumbing mistakes, and it's easy to avoid once you know what you're looking for.

Freshwater Hose

Freshwater Hose carries drinking water from your tank to your faucets, shower, and water heater. It needs to be food-safe, meaning no plasticizers or contaminants that can leach into your drinking water. Clear reinforced PVC braid hose is the old-school standard and still works well. Semi-rigid polyethylene tubing in colour-coded red (hot) and blue (cold) has become popular on newer builds because it's easier to route, kink-resistant, and connects cleanly with push-fit or barbed fittings.

Sanitation Hose

Sanitation hose runs from the toilet to the holding tank and from the tank to the pumpout fitting. It has to contain waste and, critically, it has to contain the gases that come with it.

Standard PVC hose is permeable. Over time, even without any visible cracks or leaks, sewage gases work their way through the hose wall. That's where the smell comes from. Not the tank. Not the toilet. The hose.

The fix is using properly rated, low-permeation sanitation hose. The Shields 144 Series Super PVC Sanitation Hose is one of the most widely used products of this type. It uses a multi-layer construction with an inner barrier specifically designed to stop gas from passing through. It's the right answer to a problem that catches a lot of boaters off guard.

Raw Water and Exhaust Hose

This one handles engine cooling circuits and wet exhaust systems, where the hose has to cope with both high temperatures and raw seawater at the same time. Neither freshwater hose nor sanitation hose can handle those conditions. Always use a hose that's specifically rated for raw water or exhaust service when working in these areas.

A Few Maintenance Habits Worth Building

• Squeeze every hose during your seasonal inspection. Soft spots, brittleness, or a sour smell are all signs it's time to replace.
  
  

• Flush freshwater lines at the start and end of each season. A diluted white vinegar solution works well to break up mineral deposits.
  
  

• Sanitation hose typically has a lifespan of five to seven years, but replace it sooner if odours persist despite cleaning. The hose is almost always the culprit.
  
  

 Find these on Go2Marine All Marine Hoses

Washdown Pumps: You Don't Know What You're Missing

Boaters who have never used a washdown pump often don’t see the need for one at first. But once installed, it quickly becomes one of the most useful systems onboard.

If you fish, anchor in muddy coves, dive, or regularly track sand and salt onto the deck, cleanup can take time and effort. A washdown pump connects to a dedicated hose and uses pressurized water, often drawing from a raw water intake, to rinse the deck quickly and efficiently. Instead of scrubbing stains or hauling buckets, you simply spray down the area and clear away mud, fish residue, sand, and salt in minutes. It saves time, reduces mess, and helps protect your deck from long-term buildup and corrosion.

What It Actually Does

A washdown pump delivers pressurized water, almost always seawater drawn from outside the hull, to a nozzle or hose bib mounted on deck. It runs off a simple 12V switch and produces enough pressure (typically 40–70 PSI) to move mud, fish blood, bait residue, and salt off surfaces quickly.

The four jobs it does best:

• Cleaning the anchor and chain on the way up, you're rinsing mud off the chain as it comes aboard rather than letting it pile up in the locker

• Washing down the cockpit and deck after a day of fishing, fast and thoroughly

• Flushing the bilge before the bilge pump takes over shifts debris that would otherwise just float around

• Rinsing wetsuits, dive gear, rods, and reels after use

Saltwater or Freshwater: or Both?

Most washdown setups draw from the sea, which makes sense; you're not burning through your finite freshwater tank just to rinse mud off the anchor. But if you want the option of a freshwater rinse before trailering or hosing down sensitive electronics, a dual-supply valve that switches between the seawater intake and your freshwater tank gives you both. Not complicated to install and genuinely useful.

Shurflo's Pro Blaster range is one of the most popular options for good reason: reliable self-priming, sensible flow rates, and solid construction. Jabsco and Johnson Pump also make well-regarded washdown pumps you'll find at Go2Marine.

Find these on Go2Marine Washdown pumps

How It All Fits Together

When the whole system is working well, you barely notice it. The freshwater pump pressurizes the lines so your galley faucet and head sink flow on demand. The marine toilet flushes cleanly, and waste travels through odour-safe sanitation hose into the holding tank, where it stays until you're at a marina. Sink and shower water drains away through properly sealed through-hulls. And the washdown pump handles deck cleaning without touching your freshwater supply at all.

Every part of that system depends on the others. Run a cheap non-permeation-rated hose on the sanitation side, and the whole boat smells. Install a faucet that's not rated for saltwater on the transom, and you'll be replacing it next season. Use a washdown pump with a lower duty cycle than your usage demands, and it'll burn out mid-season.

None of this is complicated; it just requires using the right part for each job. Which is exactly what this guide is here to help you do.

Get the Right Parts: Get Back on the Water

Boat plumbing doesn't have to be intimidating. Once you understand what each part of the system is doing, the decisions become pretty simple: get a marine faucet that's built for the environment it lives in, a head that works with your boat's size and electrical setup, a sanitation hose that actually seals in odours, and a washdown pump if you spend real time on the water.

At Go2Marine, you'll find all of it,  from the faucet to the hose clamp, from brands that have been building for the marine environment for decades. Jabsco, Shurflo, Dometic, Raritan, Whale Water Systems, Scandvik, Fynspray, Sea-Dog, and Shields are all in the catalogue, with real specs so you can match the right product to your boat.