When your garden pond springs a leak

QUESTION: We have a small fountain/pond in our back garden that was constructed out of river rocks and mortar about 14 years ago. The interior was sealed with something that has a slightly rubbery appearance.

Recently a section of rock and mortar near the top has been leaking water out to the adjacent garden. It’s not a fast leak, but there is chlorine in the fountain water to prevent algae, and we know that is not healthy for our plants. And the leak creates a chronic wet area.

Who can we talk to about it, or what material should we search for? We hope we don’t have to strip the old sealant out.

NANCY OBLINGERGlendale

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ANSWER: First, pinpoint the leak, says Jeff Kite, manager of Sunland Water Gardens, which builds and maintains ponds.

Is the water coming from the fountain or pond? To determine which, turn off the automatic fill and fountain pump. If the fountain is the source of the leak, the pond will maintain its water level. If the pond is the source the leak, its water level will drop.

When the water level stops falling, look above the water line. “That pretty much draws the line for you as to the source of the leak,” Kite explains.

Once you locate the source, the next step is to clean the cracked area with a wire brush. Fill the crack first with a hydraulic cement such as Stop Leak, available at most hardware stores and specialty stores such as Sunland Water Gardens, (818) 353-5131.

Seal with the proper bonding material for the pond. If it already has a rubber seal, use that; if it’s cement, use a cement seal. Kite says it’s important to use the same type of sealing material that already is on the pond because a cement-base product will not adhere to a rubber one and vice versa.

If you have fish in the pond, call a professional because the water critters have to be moved to a holding tank with proper pumps and filters during the maintenance and while the sealing materials dry.

-- Nancy Yoshihara

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