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Eliminating Pond Leaks

Pond leaks can be really annoying and troublesome to figure out. I hope this guide will help you find your leak(s) and remedy the situation efficiently. Keep in Mind that every pond will evaporate 1-3” or so per week, so adding water weekly is not uncommon. The more surface area of water you have, the more evaporation you may experience. Water loss of more than an inch per day may indicate that you have a leak for numerous reasons:

  • Splash Out– can occur when water hits the rocks in stream or waterfall that causes water to actually splash out of your pond or cause excess evaporation.

  • Channeling- pond liner has fallen at a low point at one or more places creating channels where water can escape, usually occurring in the stream or around pond edges.

  • Plants- either from the outside poking through (ex. Bamboo or Willows roots) or a landscape plant that is actively growing roots inside of the pond or stream which are actually causing a leak or making it appear so.

  •  Where Liner Attaches– many ponds have skimmers and / or biological waterfall/filter/weirs that are actually outside the pond and the liner is attached to it with brackets, silicone and screws. In time the seal can break causing leaks and may need repair or resealing.

  • Plumbing & Connections- the hose or pipe and plumbing connections may be leaking or split during a cold period or damaged somehow.

  • Basin or Pond- the actual pond basin itself may have holes or cracks (plastic pre-formed or concrete).

How to Check for Leaks in Ponds & Water Features

1. Examine. So after considering these reasons listed above, take a good look at your pond while it is running. Check the entire perimeter for any liner that may be pushed down or a rock that may have fallen where it should not be. Also look for wet spots and excessive splashing or “splash out”. If you see any evidence, then fix it / reposition the liner and watch water level to see if you have corrected the problem.

2. Check Basin- “Set Test”. If your pond is still leaking or no evidence is found then you need to determine if the leak is inside the pond basin or outside of the pond. To do this, turn off your pump for 6-8 hours (or more if needed) in the evening (is best) and note the water level. You may need to provide additional aeration for fish. The next morning check the water level- if it is the same then the pond basin itself is not leaking.

If the water level drops, then the basin itself has a leak.  Ideally you let it drop to the lowest point (without harming your fish, remove them if needed). When it stops leaking then the hole(s) are around the perimeter. You may need to remove rocks, plants and fish to repair the damage (see how to repair leaks). Check your skimmer for wet spots and areas where the screws have rusted or not completely sealed- reseal if needed. If you have a bottom drain (more common in cement ponds) that is not sealed properly that could also be creating a leak. Once you repaired the damage replace rocks, plants and fish and add water to fill pond. Monitor your pond daily to make sure you fixed the leak.

3. Check Stream, Waterfall Areas & Plumbing. If the pond basin does not drop, then the leak is somewhere else. Most leaks are usually found in the waterfall or stream areas. You can take another look at it while running to see if you can find the leak (see Milk or Dye test). If you have found no evidence then you may have to remove rocks and look for actual holes in the liner. The Biofall or Weir may also be leaking, look for wet spots or areas where they are not completely sealed, or (rarely) the fittings that connect to the weir in the back could be leaking. The pipe or hose that connects the pump to the weir may also be an issue as cracks can occur during freezing weather in winter that can also cause leaks. If plumbing is suspected, then you would need to bypass the plumbing, run your pump (or a different one) with new hose into the biofall filter or stream area. Let this run for up to 24 hours to see if the level drops. If it does, then the pipe or hose could be leaking and would have to repaired or replaced.

Dye or Milk Test. This may be done to help determine where water is leaking out. The idea is to Pour milk or Pond Dye (better choice) around the edges inside pond and stream. If it is leaking, then the discolored water or soil may help determine where a leak is by following the path of discolored water. If using milk, do a water change or clean the pond to dilute the milk. Pond dye will fade in time and is environmentally friendly. This may or may not be a useful tool for you, we usually do not recommend this method but it is “out there” online so you may see this thinking that it is a common practice.

Determine Gallons Lost per Day: To calculate how many gallons are actually being lost each day, we first measure how many inches were lost in a 24-hour period.

Do the bucket test: using a 5gallon bucket, determine how long it takes for your hose to fill it.

5 gallons in 60 seconds is 5 gpm (5 gallons per minute or 300 gallons per hour)

5 gallons in 50 seconds is 6 gpm (6 gallons per minute or 360 gallons per hour)

5 gallons in 45 seconds is 6.8 gpm (6.8 gallons per minute or 400 gallons per hour)

Then determine how long it takes to fill you pond with your hose by multiplying the time by gallons per minute based on your bucket test. So if it takes you a minute to fill 5 gallons, and 10 minutes to fill your pond, then you have lost 5×10=50 gallons lost per day.

After you have found the leak- Next step then is to repair the leak.

To repair pond liner, using a patch kit or cover tape:

1. Clean the area, remove all debris and then Dry it completely.

2. Apply a primer or rubbing alcohol to the area as directed on the bottle. You may need to use a green scrubby pad to roughen the area if applying a large amount of cover tape. If repairing a small hole then roughening the liner may not be needed.

3. Apply the patch or cover tape piece (cut to size prior to applying) over the hole allowing several inches of overlap on either side of the hole. You may need to use a hand roller to smooth out air bubbles.

4. Allow to set and dry for several hours or as directed on the patch kit instructions.

5. Replace rock and recover the area once “cured”.

If your pond is made with cement, then you will have to use a special concrete sealer over the crack. Clean and dry area prior to applying the sealer. This may take up to 24 hours to set or cure, follow the manufactures directions.

If you need more help Contact our Store Associates (360-412-0309)

or our Pond Maintenance department (360-280-5116) when you need help you with your pond issues.

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