Pond Is Losing Water: Water Loss Troubleshooting Guide


It can be frustrating watching your pond lose water and not know where to start or how to fix it. Don’t worry, this guide will take you step by step on what to do to find the problem and fix it.

The most common cause of pond water loss is due to evaporation. Evaporation accounts for about an inch or two a week of water loss in most cases. If you are losing more than that, you possibly have a leak in your plumbing system, stream, pump, or the lining of the pond.

In this troubleshooting guide we will cover all the possible reasons your pond is losing water and how to fix them. In most cases the solution is an easy fix, if you know what you’re looking for.

Pond Water Loss From Evaporation

Evaporation affects every pond and is the leading cause of backyard pond water loss. A pond will typically lose around an inch a week to evaporation, and in the summer months when the air is hot and dry, it could be more. Also, with less rain falling in the summer months, many pond owners notice the decrease in water levels and think there may be a leak.

The only way to really remedy water loss due to evaporation is to try planting tress or bushes around the pond to get as much of the water in the shade as possible. Direct sun light will increase evaporation, especially on hot dry days. Water covering plants like water lilies can also help reduce evaporation.

If you are losing less than 2 inches per week of water, that is normal, and I would chalk it up to evaporation. If you want to make absolutely sure of the amount of water that should be evaporating from your pond, check out this Pond Water Evaporation Guide I made for you. It will walk you through the entire process and calculations needed to figure out how much water should be evaporating from your pond.

Pond Water Loss From Plants And Fish

Ok so you’ve decided the water loss you’re seeing in your pond is a lot more than just some evaporation. Now we need to start troubleshooting what the problem is. Many people will think the plants in their pond or the fish are drinking up the water.

This is typically never an issue. The plants and fish will most likely not consume enough water to outweigh just normal rainfall. I’ve heard stories of people getting rid of their fish or removing plants because they thought it was causing water loss. You don’t need to do that. If you are losing more water than just standard evaporation will cause, it’s most likely a leak somewhere.

Waterfall Or Stream Leak

If you have a waterfall or stream that is feeding your pond from a pump, this is most likely where your leak is. This won’t be the only possible location for a leak, but is definitely where you should start your investigation.

A lot of times the ground will settle, causing the stream or waterfall to spill water somewhere along the way. Check for wet or damp spots on the ground along the stream and around the water fall. Move rocks out of the way and shut off the pump if you need to. A lot of the time, the leak can be fixed by relocating some rocks or re-configuring your stream.

Some Things To Check:

  • Does the water flow freely
  • Are obstacles causing water to pool in certain areas
  • Do you need to better channel the water stream
  • Are plants causing the water to dam up
  • Can you prune some of the plants to prevent a sponge effect

Also keep in mind the water splashing from a water fall. On windy days, the water can be swept out it’s normal path. This will lead to an increase in water loss over time. A couple well placed plants can help reduce water loss due to waterfall splashing. If your waterfall and stream seem fine, the next thing to check is your plumbing.

Check Pond Edges

After checking the edging of the stream and waterfall, check the edges of the entire pond itself. Many times after the ground has settled the lining will be folded over or not placed properly to keep the water in the pond. If your pond edges are made up of porous material like wood or light rock, the water may be seeping out there.

Check the surrounding areas of the pond for wet or damp areas that could help pin point where the leak is coming from. Make sure the ponds edges are all at an appropriate level. Low spots in a ponds edge is a common reason for pond water loss.

Double check that the lining is pulled up to contain the water all around the pond. If not secured properly, a pond liner can easily become detached and allow water to make its way out of the pond. Secure the pond liner with heavy rocks or decorations.

Water Leak In Pond Plumbing

The pond plumbing includes everything from the inlet, pipes, check valves, skimmer, and filters. To start, turn off the pump and make sure your check valve and filter boxes remain full of water. The check valve (backflow preventer) may still lose water if it is faulty, but that doesn’t necessarily mean you have a leak. Either repair or replace the check valve before continuing the test.

If the water filter level stays the same, then your check valve, filter box, and underground plumbing are good. If you notice the water level dropping however, and you’re sure you don’t have a faulty backflow preventer, you most likely have a leak here.

Things To Check:

  • Filter box connectors
  • Pipe fittings
  • Plumbing joints
  • Pump connectors

Check all the connections to your filter box and pipes. Check the connectors to the pump as well. If you have PVC or plastic connectors, they will sometimes crack over time. This is true for pipe joints and underground piping also. After replacing any leaking parts, seal them with pipe sealant or pipe putty to help prevent future leaks.

If you think the plumbing issue is more than you can handle yourself, look into HomeAdvisor PlumbingOpens in a new tab. to hire a local professional to help you out.

Water Leak In Pond Lining

If your plumbing is holding water fine, the next possible cause for water loss is a leak in the pond lining. To check if the leak is in your pond lining, simply turn off the pump and mark the water level in the pond. Check back in a day or two to see if the water level has dropped.

If you do have a leak in the pond lining, you’ll need to find it and patch it. There are a couple ways to find a leak in a pond lining. You could use the colored dye method or the drain method. If you have fish in your pond you will want to relocate them before trying the drain method

Colored Dye Method:

  • Turn the pump off
  • Drip some bright colored dye into the water near any suspected leaking areas
  • Watch the dye for 10-20 minutes
  • Notice if the dye is moving to a certain area of the pond
  • Watch for streaks in the dye leading to any leaks
  • Apply more dye drops as needed in areas of concern

Pond Drain Method:

  • Turn off the pump
  • Let the water drain from the pond
  • Keep checking the water level until it stops dropping
  • Add more water to the pond
  • Verify the water stops draining at a certain point each time

Once the water stops draining from the pond, you can be pretty certain the leak is at the water line of just above it. Slowly make your way around the pond looking for a tear or rip in the lining. Sometimes even a small hole in the lining will cause a leak and be very hard to locate.

Once the leak has been located, you will need to patch it before filling the pond again. They sell pond lining patch kits for under 20 bucks online. You may be able to find one at a local home improvement store, but I’ve had better luck just ordering online.

After you’ve patched the leak, put enough water in the pond to cover the patch and wait a few hours to a day. Check back to make sure the patch held before you finish filling the pond the rest of the way.

Bottom Drain Leak

If your liner looks in good condition and you have a drain at the bottom of your pond, or the inlet to your pumps plumbing, you should also check that inlet seal. Sometimes the seal will wear out over time and the plumbing may have passed as good, but the seal around the lining and the inlet is leaking.

These are dire times if the inlet is at the bottom of your pond because you will have a completely empty pond at this point. Manually pour some water in around the bottom of the pond and check if the water leaks out the inlet. You should notice some bubbles or the water slowly draining if you have a leak here.

Most of the time this can be fixed with a new inlet or resetting the seal the liner makes with the inlet. In some cases you can apply some caulking around the area to plug any leaks. Before filling the pond back up all the way, pour just enough water to cover the inlet to make sure it is sealed up.

Check For Critters

Keep an eye out for critters around your pond that could tear your liner. Rats, rabbits, chipmunks, and mice for example, will burrow into the ground near your pond. If they get to your liner, they will most like chew on it causing a tear. A popular hot spot for critters is under and around the waterfall feature.

Walk around the outside of your pond and check for any possible holes dug by critters and get rid of them. Also check in between your liner and where the liner is held to the ground. Sometimes they like to burrow in between the liner and make a little nest.

This is probably the least likely scenario, but has happened before. If you have a fenced in yard, you’re probably fine. But there have been pond owners who have noticed the neighbor pets drinking from the pond and noticing some water loss over time because of it. I really hope it’s as simple as that, but most likely not.

Wildlife Consuming Water

There is a chance that nearby wildlife or even your own pets could be consuming the water. For example, birds may use the water to bathe in and fly off taking some water with them.

This is a very minimal amount of water and is probably not the cause of any real water loss. Do keep in mind that a family of deer could make the water level drop a bit. But this wouldn’t be an ongoing problem in most cases, and probably not the cause of major pond water loss.

Pre Built Ponds

If your pond is less than a couple years old and was installed by hired professionals, there may be a warranty or something you could take advantage of. A good contractor will usually back their work for some time. Especially a backyard pond that shouldn’t have any problems in it’s first few years.

Robert Sampson

I'm Robert Sampson and I live in Colorado where I spend a lot of time in the backyard with my family either grilling, playing games and sports, or working on a project to make our backyard a better place to be.

Recent Content