Troubleshooting Your Boat’s Fresh Water System

Fresh water systems in one form or another (even as simple as a bucket or a barrel with a cup on a string) have been on boats since man ventured far enough away from land to need liquid refreshment. These days, though, if your boat was designed for cruising, or with entertaining capabilities on board, chances are good you’ve got at least a basic manual or electric-powered water system on board.

A simple galley with a fresh water mixer and sink on a modern power boat. Cutwater photo.

A simple galley with a fresh water mixer and sink on a modern power boat. Cutwater photo.

And, like most systems on boats, it’s likely one that you’ll need to troubleshoot someday. To keep things simple we’re going to be talking about water systems with basic manual and electric pumps and a single fresh water tank. Systems with hot water heaters, sophisticated filters, and accumulator tanks add too many layers of complexity to discuss here, but bear in mind that simpler systems are always easier to troubleshoot and maintain.

Electric Fresh Water System: Pump Runs with No Water Flow

What’s the first and most obvious thing to check if you’ve opened a fresh water fixture on your boat and can hear the pump working, but find that no water is flowing? Make sure your water tank actually has water—you’d be surprised how many times it’s as simple as that. If you find the tank empty, fill it up and then try turning on the water (galley faucet, shower head, fresh water washdown, etc.) again.

Second, make sure that any valves in the water line haven’t been shut inadvertently. Often you’ll find one near any filter that’s been installed in the line near the tank. While you’re there, check the filter for obstruction.

If your water tank is full and the valves are open, but you’ve still got no water flow, it’s time to start working the problem from the water fixture back to the pump. First flip off the circuit breaker for the fresh water pump. Next, get underneath the fixture and remove the water supply hose by loosening the hose clamp(s) and pulling the hose off. You can be well-prepared for the possibility of a pressurized gush of water from the supply hose by wrapping a towel around the end of the hose as you pull it off.

A typical electric fresh water pump. Note the distinguishing names and numbers on the pump motor, which make finding parts much easier. Shurflo photo.

A typical electric fresh water pump. Note the distinguishing names and numbers on the pump motor, which make finding parts much easier. Shurflo photo.

Once you’ve got the hose off, put the end of it in a bucket, making sure you prevent it from flying away when the water pump is turned back on by securing it in the bucket with a piece of electrical or duct tape. If water comes gushing out of the hose when you flip on the breaker for the water pump, you know that you’ve got a problem in the fixture. This is actually quite rare. Water fixtures almost never fail “closed,” rather they usually leak badly before completely failing—so it’s unlikely you’ll run into this scenario. But if you do, you may need to go to your local marine supply store and seek out a rebuild kit for the fixture, which usually contains all sorts of washers and seals. If your fixture is really old, it also may be corroded inside and need replacing; you’ll find out if this is the case when you start disassembling it.

The other thing that may happen is that no water comes flowing out of the hose when you flip on the breaker. If this is the case, turn the breaker back off and go back to the discharge end of the fresh water pressure pump. To ensure the pump is working and the hose is not simply blocked or kinked, remove the hose from the discharge end of the pump and place a bucket in the area, or a lay down a large beach towel. Flip the breaker back on again. If the pump sprays water freely, you probably have a clog, kink, or break in the fixture supply hose. You can try to loosen clogs with your own lung power by blowing on one end of the hose or attaching an air compressor or shop vacuum hose wrapped in duct tape. Abrasions or holes and kinks can generally be spotted by eye—simply examine the full length of the hose. Replace the hose if you find any holes. You can usually fix kinks my rotating the hose and pressing out the kink. Check for water flow once you’ve addressed any supply hose problems.

A typical electric water pump rebuild kit contains seals, diaphragms, and other internal parts. Shurflo photo.

A typical electric water pump rebuild kit contains seals, diaphragms, and other internal parts. Shurflo photo.

The worst-case scenario is that the fresh water pump does not spray any water after you’ve taken off the hose from the pump’s discharge end and turned on the pump at the breaker. But there’s one more thing you can verify before throwing in the towel and rebuilding the pump. Check the supply hose from the water tank by removing it from the pump. If water flows freely, you’ve ruled out a clog. You can also go as far as to inspect the hose for kinks like you did with the fixture supply hose. But if the supply hose from the fresh water tank checks out okay, it’s most likely that your fresh water pump is in need of a rebuild. Don’t worry; it’s not as bad as it sounds.

Source parts by taking pictures of your pump, or by writing down any distinguishing part or serial numbers, a brand name, or other numbers found on the pump, and then head to your local marine supply shop. If you don’t have one near you, go online and try a Google search using any of the numbers or brand names on the pump itself. Pump rebuild kits generally contain seals, a new diaphragm or impeller, inlet and outlet valves, and most of the important rubber parts.

We recommend carefully removing the entire pump from the boat and taking it home to do the rebuild. Here you can disassemble it and keep track of all the parts and pieces as you take it apart. A galley or saloon dinette table will suffice. This will save you from dropping pump parts down the bilge. Trust us; we’ve done it.

Once you’ve completed the rebuild you can reinstall the pump and run it to check for proper operation. One part that is not included with most rebuild kits that can cause problems is the pressure switch. If your pump is still having problems after a rebuild, you might want to try replacing its pressure switch, which regulates the maximum pressure at which the pump delivers water. Generally it’s an inexpensive part.

Manual Fresh Water System: Actuating Pump Produces No Water

If you’re lucky—hey, we’re old-fashioned—you’ve got a very simple water system onboard with manual pumps that are actuated by hand or foot. This type of system is generally much easier to troubleshoot than one with an electric-powered pump because of the simplicity of manual fresh water pumps. These pumps come in two varieties: hand pumps that mate fixture and pump in one unit, and foot pumps that deliver water to a separate sink fixture.

If you find yourself pumping away at your hand-operated galley sink fixture and no water comes out, you can easily troubleshoot the problem in a step or two. First, as mentioned earlier, check to ensure your water tank is full, any valves are open, and any filter is clear of obstruction. If you’re still having trouble getting water, move on to the next step.

Manual fresh water pumps like this basic model from Whale are generally easy to troubleshoot and rebuild. Whale photo.

Manual fresh water pumps like this basic model from Whale are generally easy to troubleshoot and rebuild. Whale photo.

Remove the fresh water supply hose from the hand pump to see if water is flowing from it. If water flow is not present you can try moving the hose end to a lower point in the boat or simply try sucking on it like a straw. If there’s good water flow, then your hand pump likely needs a rebuild. If there isn’t water flow, check the supply hose to your hand pump using the methods described earlier to rule out any kinks, holes, or blockages.

These fresh water fixtures/hand pumps are extremely easy to rebuild and parts to do the job are generally easy to source from your local or online marine supply shop. Source parts by looking for identifying numbers or names on the pump, taking pictures of it with your smartphone or camera, and then taking it to a brick-and-mortar shop, or doing a Google search online with any of the identifying numbers or names. As with an electric fresh water pump, we recommend taking your manual pump off the boat to rebuild it—or try using your dinette table. That will help prevent unintended sacrifices to the bilge gods.

Foot-actuated pumps are a little more complicated than hand-actuated fresh water pumps but are easy to troubleshoot and rebuild. Whale photo.

Foot-actuated pumps are a little more complicated than hand-actuated fresh water pumps but are easy to troubleshoot and rebuild. Whale photo.

If you’ve got a foot pump that pumps water through a fixture at a sink, troubleshooting it is much like the hand-pump procedure just described. Check the fixture itself for a clog.  Check the supply hose to the fixture for a clog, kink, or break. Then detach the supply line to the pump and check for water flow by sucking on the hose or by moving the hose end to a lower part of the boat. If there’s good water flow to the foot pump and you’re still having trouble getting water to spurt from it, it’s probably due for a rebuild. You can source parts as previously discussed and take a short afternoon to rebuild the pump at your leisure.

The good news is that fresh water systems are pretty reliable, needing much less fussing over than marine heads, electrical systems, and other onboard troublemakers. Tackle the problem with the methodical approaches we’ve suggested and you’ll be up washing up the dishes again in no time.

 

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