Water may overflow from a Pondless Waterfall reservoir when the pump shuts off because water remaining in the stream, waterfalls, and plumbing drains back into the underground reservoir.
If the reservoir is overfilled or does not have enough storage capacity, the returning water can cause it to overflow.
Common causes and solutions
- Reservoir overfilled: Adding too much water while the waterfall is running can cause the reservoir to overflow when the pump shuts off. Allow the water to drain back into the reservoir before checking the water level.
- Reservoir too small: The underground reservoir must have enough capacity to hold the water circulating through the waterfall and stream. Aquascape recommends a reservoir capable of holding approximately twice the stream's water volume.
- Water draining from plumbing: When the pump stops, water in the plumbing may flow backward into the reservoir. A properly installed check valve can help prevent this additional backflow.
- Automatic fill valve set too high: If an automatic fill valve is installed, an excessively high fill setting may leave insufficient room for water returning from the stream.
How to prevent the reservoir from overflowing
- Turn off the pump and allow water from the waterfall and stream to drain back into the underground reservoir.
- Check the water level through the inspection port on the Pondless Waterfall Vault. The water should remain contained within the reservoir.
- Check for overfilling. If the reservoir is too full, remove excess water.
- Inspect the check valve, if installed, to make sure it is operating properly.
- Evaluate the reservoir capacity. If the reservoir continues to overflow, additional underground water storage may be necessary to accommodate the returning water.
Important: Do not permanently lower the water level without confirming that the pump will remain adequately submerged while operating. Insufficient water can cause the pump to run dry and become damaged.
If the reservoir continues to overflow after these checks, a Certified Aquascape Contractor can evaluate the reservoir's storage capacity and installation.