7 Factors of Pond Evaporation

Lily pads in outdoor water features
Pond evaporation can fluctuate. Here in Colorado we get a wide variety of weather from one minute to the next! If you are wondering if the water loss you are seeing is part of evaporation, read these evaporation factors.  It is very important that the water level is topped off, whether by your autofill or by hand to keep your pond healthy.

1. Humidity (or lack of!)

Colorado can be very dry!  If you live in Colorado you know that when the humidity gets up around 40 or 50% we feel sweaty! But often we get 12% or even 7% humidity!  This can increase the evaporation rate of a pond.

2. Heat

When the heat rises you may see an additional inch or two of pond evaporation.

3. Surface Area

Whether a pond is 3 x 5 feet or 20 x 25 feet, it will lose between 1 and 3 inches a week.  However, if your water feature has a long stream or waterfall, it will add to the surface area, and therefore add to the water loss within the pond.

4. Shade

The microclimate plays a role in the evaporation of the pond water.  If your pond is on the north or south side of the house with no shade from trees you will see more evaporation.

5. Plants

Some may think that the pond plants are sucking up all the water.  However, they drink a relatively small amount.  In fact, if your pond has water lilies, they are reducing the amount of surface area and are actually reducing the amount of evaporation occurring.  We have experienced a case in which a willow tree had gotten its roots into a pond and sure enough, that tree drank a lot of water!

6. Wind

Wind is the worst when it comes to water evaporation!  When it is windy you may see a daily difference in water loss.

7. Leaking

If you are seeing 4 or more inches of water loss in a week, you may have more than evaporation on your hands; you may have a leak.  Check out our Leak Diagnosing Tips. 

1 to 3 inches of evaporation in a pond per week here is normal.  Add water weekly so that the pump doesn’t run dry.  Remember, if you add more than 20% of the total pond volume you’ll need to add a pond detoxifier when you do that, to protect your fish from the chlorine in the water.  If adding water isn’t always easy to do because of a busy schedule, give us a call to talk about adding an autofill at 303-775-0224.