07851 810426 info@pondstarsuk.com

At this time of the year we tend to get a lot of phone calls from clients thinking that they have a leak on their pond, however, this may not be the case. We have decided to put together a little information and a check list to help you, the pond owner, define if you have a leak on your pond, or the drop in water level is just due to water evaporation.

As a pond owner you will experience a loss of water, a drop in the level of water due to water evaporation, and this will happen all year round to a lesser or greater degree. On average a pond can loss anything from 1” to 4” over a period of a week, depending on weather conditions.

The amount of water that is “lost” depends on a number of factors, these include the overall temperature, cloud cover, shade over the pond, humidity, wind and the design specifics of your pond and/or water feature, such as a waterfall, fountain and stream, and the planting that you have in and around your garden pond.

Ground Level Koi Pond, with natural stone edging.

Ground Level Koi Pond, with natural stone edging.


Lets take a look at all these factors in a little more depth…..


Weather Conditions

Weather conditions WILL influence the water level of your garden pond.

Humidity – With low humidity and warmer temperatures there will be a drop in the water level, in some cases we have seen over three inches of water loss in just a week.

Sun – Ok, so this seems like an obvious weather factor, the more sun you have the more evaporation your pond is going to experience. You WILL notice a larger, more dramatic drop in water during the sunnier days of the year, and this doesn’t mean just the summer months, water can evaporate with the help of the sun all year round. In the winter the pond water may well be warmer than the outer air and evaporate.

Wind – This is technically called evapotranspiration; a high wind means more evaporation.

Believe it or not the wind picks up the water straight up and out of your pond, moving it to other places. Take into account if you have a waterfall running and or a fountain, then the wind can take a portion of water away too.

Pond Stars UK - Water Feature - Dorset

Water Fountain can increase the water loss from your pond.


If your pond has been designed with natural rocks and pond plants have been incorporated into the overall design, this will also affect the level of water on your pond.

Plants – These will also absorb water, more so on a warmer day, this process is known as wicking. Wicking occurs when a plant and/or its roots hang into the pond water which allows the water to slowly “wick” out (the plant is drinking the water up). A pond with plants will lose more water and will need topping up on a more regular basis.

Natural Rocks – Rocks will also soak up an amount of water, particularly newly installed around the ponds edge. There will always be a water line on a rock above the actual water level, where the water has been absorbed.

Pond Level – This will not be so much of a factor in a concrete or fibre glassed pond, however, the level of the pond itself will affect the water level if it is not level in the ground, there may well be an area where water can flow freely out of the pond!

Pump – Large pumps pushing high volumes of water may also have a larger evaporation rate.

Pond Stars UK - Dorset - Natural Rock Pond Edging

Natural Rock will absorb an amount of pond water too.

Taking all the above into consideration it is important to measure the water level of your pond as accurately as you can, especially if you suspect more than evaporation is causing your ponds water level to drop.

Always measure your water level from a specific place and from that same place every time.

The ideal place is with a skimmer, that has an overflow in it, here you will be able to take a more accurate reading.

There are a number of things to trouble shoot prior to further investigation for a pond leak when you have a drop in level on your pond.

  • Test the water level – fill pond to its designated water level, measure and leave for 24 hours, measure again from the same spot. Do this over a period of a week, to see if the drop is consistent or weather affected.
  • Check for low edges – as a pond settles low spots can occur and water will escape.
  • Splash “leak” – The water from the waterfall may be going over the edge.
  • Obstruction – Rocks, planting and algae on a waterfall or in a stream can divert the flow of the water to over the edges.

If you have done all the above and it still appears that the water level is dropping, we would advise you to turn your pump of for 24 hours (place an air stone in to keep your fish stock happy and alive!). Again make sure that the pond is filled to its appropriate level, measure and check again after the 24-hour period, if water level still drops this is an indication there may well be a leak.

Double check the area as to where the water level as dropped to, this could be where the leak is located.




Do you suspect that your water loss is due to a pond leak? Contact Pond Stars UK today info@pondstarsuk.com Or call Katie on 07831 244659 to arrange for a viewing on your pond.

We cover all aspects of pond maintenance in Bournemouth, Poole, Wimborne, Dorset and surrounding counties