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Water Feature Troubleshooting
Leak Detection

Troubleshooting, as Sherlock Holmes might say, is the art of gathering evidence, eliminating as many variables as possible until what you have left is the solution. We will accomplish this by isolating the system into parts. By testing and observation, we eliminate one segment after another until we have isolated the problem. For instance, if the pump doesn't work at all, we don't have to look for a clogged filter. Conversely, if the system works good with the backwash valve on 'recirculate' but we don't get sufficient flow on 'filter', the pump is not the problem. Troubleshooting problems generally fall into one of three categories, electrical, plumbing and leak detection. Below is a sequence of information and questions to help you isolate the problem.

If you don't have experience with electricity or are not familiar with the terms mentioned, please consider not doing your own electrical work. Local laws and regulations take precedent over anything written here. Before going through a bunch of gyrations trying to figure out the problems, check the obvious: GFI, circuit breaker.

Yes. Go to Plumbing
No. It is a new installation and the pump has never been on. Check to see if you have wired it right according to directions. If either the = GFI or the circuit breaker continue to trip, check to see you don't have a loose strand of wire grounding out in back of the pump. If it seems wired ok, see paragraph below.


  • Check the circuit breaker and GFI again to see if either one is tripped. For a circuit breaker you must first switch it all the way off before you can turn it on. These are usually found outside the house in a box on the side of the garage or the house near the meter. Everyone should have a Ground Fault Interrupter (GFI) circuit breaker or an in line GFI. These are required in bathrooms and kitchens near water or outside. They trip when any tiny bit of juice is lost. (A regular breaker trips when they heat up which takes time) GFI's have a test and reset button. The reset button should stay in when pressed. If the GFI reset button does not stay down, you are probably not getting juice to it. GFIs and especially GFI circuit breakers can go bad.
If this still doesn't do it plug something in near the pump. Now don't you wish you put a plug nearby? If what you plugged in works and the pump doesn't, you need a new switch or a new pump. You can test for power to the switch and pump, but you should have some knowledge of electricity or get someone who does.
  • Check to see if electricity is getting to the switch using an amp meter set on 120v, red test lead to hot side of switch, black lead to white (common) or directly to ground wire. If OK, repeat the same procedure after the switch, make sure it is on.

  • To check the electricity at the pump it is necessary to remove the cover plate at the dry end. If your pump is 110v, you should have a hot wire (usually red or black), a white (common) and green (ground). With switch on, you should get 110-120v when you go between the hot and white wires.

  • On a 220v pump, you have two hots and a ground. Each hot should read 110-115v with the other test lead to the ground wire. The two hot wire need to come off different legs from the circuit breaker panel. If this doesn't make sense, don't do it yourself.
If you need a new pump, go to our catalog for a great selection of energy efficient pumps. Remember, all pumps should be properly grounded.

This is usually caused by undersize wiring especially if distant from the source. Many pump installation instructions call for 14 ga. wire but we never use any thing smaller than 12 ga.

If the pump had worked before but now only hums, you may have motor problems or have a pebble stopping the impeller from turning freely. Manually turn the shaft and see if it turns freely. If not, see impeller cleaning.
With a new pump that only hums, follow the impeller cleaning instructions. There has been only one new pump that we installed that had problems starting. It was a two speed pump that would work on high but not on low. Apparently the bushing on the housing wasn't pressed right. If these hints don't help, contact us at technicalquestions@PFPros.com and describe the symptoms and we'll reply.


We have already trouble shot enough to know the pump is working OK so the problem must be in the plumbing. Several common problems are low water level, dirty baskets, clogged intake, air leaks, dirty impeller and dirty filter.

This condition probably means your check valve is stuck open. See if you have a spring type check valve, get rid of it. They restrict flow too much and are very easily clogged. If you need to replace it, look at our clear check valves with unions.

If you don't have any blockage, you probably have an air leak or an air lock. so you loose your prime. If it worked OK in the past, you may have debris on the 'O' ring of the leaf trap lid. Clean and lube. If the 'O' ring has been stretched, get a new one. Check with local pool companies. You can get silicon lube from us or at a swimming pool supply.

If the pipe from the pond skimmer goes up for a run then drops down to the pump thus trapping air in the pipe. You may have an air lock in the intake pipe from the pond to the pump. You may be able to prime the pump two or three times to suck out all the air. If the problem persists, put a tee in the intake pipe at its highest point with the stem up. Reduce the opening to 1" and put in a ball valve. When you need to prime the pump, open the valve and fill the pipe with a garden hose. Having the tee at the highest point in the pipe allows a way for the air to get out. Be sure to close the valve when the pipe is full.

or is better after you backwash then slows after a few hours.

  • make sure all leaf traps are clean
    TEST Put the BWV on recirculate (thus bypassing the filter). If the flow returns then the sand in the filter is caked. See the maintenance section how to deal with sand filter cleaning.
If this is not it:
  • it is possible that algae, pine needles or gravel has been caught in the pump impeller. If the plumbing is not too crazy, you may be able to open some unions and then splitting the pump housing to get to the impeller. see impeller cleaning.

If you don't have a proper skimmer with leaf basket, you could get leaves clogging the intake pipe. You may be able to open the leaf trap at the pump, stick a hose down the intake pipe in the pond, seal around the hose the best you can and give it a blast. If you have to, go to the hardware store and get what I call a pipe bladder. It connects to the end of a garden hose. Remove the skimmer basket and put the bladder into the intake pipe. Hold it there while an accomplice turns on the hose. The bladder will expand, sealing opening and squirt water back toward the pump. If you don't have a check valve online, you may be able to go back toward the pond. If this still doesn't work, get the plumber's snake or call a plumber and go to plan 'C'. (This bladder is also good on drains)


Looking for a leak uses much the same methods as we use in other trouble shooting. We isolate segments of the system in order to eliminate the parts that work and what we have left is the problem area.

Whenever you check for water loss, let the water run for a while so the system is balanced before taking any measurements.

The first question is whether the pond is losing water all the time or only if the pump is running. If you are losing water only when the pump is on, then the leak is after the pump, probably in the waterfall. Likely problems are:

  • plants or other debris have 'dammed up' parts of the stream bed thus causing the water to overflow.

  • if you have a liner stream bed, possibly the edge has been pushed down allowing water to escape.

  • if you have a concrete stream bed there may be a crack in the concrete. Usually the cracks are bigger on the edges and smaller in the middle. If you have a crack on one side of the stream bed, be sure to check on the opposite side. Often the crack are at the thinnest part of the stream bed or where the stream bed meets the pond. These cracks are caused because the dirt below the stream bed has settled.

  • If rock were mortared together with the idea that this joint would hold water, you've got problems. You may be able to find the leaks but they could be very numerous. Often they are found on the lower side of the rocks because the mortar slumped away while still wet. You may want to consider taking it all out and putting a liner underneath and redoing it.

If you are losing water all the time, even when the pump is off, the problem is found below the water line. This may be in the pond or in any plumbing below the water level. For a system with an external pump, segment the system further by plugging or capping the pipe going to the pump. This can be done inside many skimmers with a male fitting and a piece of pipe that extends above the water level. If you have a three way valve on the return, close the side that goes back to the pond (thus separating the pond from the plumbing). With this method, you can look down the pipe to see if the water level changes within the pipe or remains the same. If the water level goes down look further at the plumbing. Hopefully you don't have to do much digging. Look for areas that remain wet, even down hill from the site.

If you lose water when the pump is off and get a lot of air in the leaf trap and filter, the leak may be on the intake side of the pump, If you don't get air in the filter, the leak should be after the pump but still below the water level of the pond.

If none of these tests have isolated the leak then the only place left is the pond itself. Allow the water level to drop below the perimeter shelf if you have one. If the water level keeps dropping, the leak is still lower. If you are patient, you can wait for the water level to stop falling. When it does, you have found the lowest part of the leak. Look around the water level for the problem. You may need to put the fish in a temporary tank while proceeding. In concrete ponds, look for cracks, areas that stay wet, and check around any pipes skimmers and bottom drains for loose concrete or gaps. A lot of times if you start poking around with an old screwdriver or ice pick you can dislodge pieces of concrete and soon push the tool up to the handle.

If the water level stops going down at the perimeter shelf, that's where the leak is. Depending upon your situation, you may dig some hole outside the perimeter to see which ones fill with water and which remain dry. In those with water, see from which way the water enters. This may take emptying it a few times and patience.


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