Posted on July 12th, 2025

If you’ve ever looked at your pond and thought, “Where did all the water go?”, you’re not alone. Before jumping to conclusions, it’s important to understand what evaporation is—and what it isn’t.

Evaporation occurs when water turns into vapor and escapes from your pond. How much water you lose depends on your region and the time of year. In our area—moderate temperatures and higher humidity—you can expect around 1 to 1½ inches of water loss per week during spring and summer. Most of this will be replenished naturally by rainfall.

In hotter, drier climates, evaporation can exceed 3 inches per week, especially if your pond has waterfalls or streams. Moving water exposes more surface area, which means ponds with cascading waterfalls or flowing streams can lose 2 inches or more in a single day! In contrast, larger ponds may barely notice this effect because the water volume dilutes the loss.

What It Isn’t

Evaporation doesn’t happen overnight. If you fill your pond one evening and wake up to a 5-inch drop, you’re likely dealing with a leak—not evaporation. Rapid water loss is almost always a leak, so it’s time to investigate.

Check for Low Edges

The most common cause of leaks—especially in new ponds—is settling at the edges. Streams and waterfalls often settle slightly after construction or rainfall, creating low spots where water can escape.

• Inspect the edges of your pond, stream, and waterfall.
• Look for wet mulch, gravel, or muddy spots around the perimeter.
• Fix minor leaks by lifting the liner and adding soil beneath it to raise the edge above the water level.

Watch for Splash Leaks

Sometimes water isn’t leaking—it’s splashing out. Check your stream and waterfall rocks. Adjusting the rocks can redirect water back into the pond and stop the “splash leak” without any extra materials.

Check for Obstructions

Rocks, plants, algae, or even wildlife can block the flow in streams and waterfalls, causing water to divert over the edge. Trim plants and remove debris to ensure smooth flow. BIOFALLS® filters should also be checked for proper operation. These simple adjustments often fix the problem quickly and affordably.