Building an Outdoor Water Feature Plumbing Guide

Choosing the Right Pump

The pump is the heart of any water feature. Submersible pumps sit inside the water and are ideal for most residential fountains and small ponds — they are quiet, easy to install, and relatively inexpensive. External pumps sit outside the water and are better for large ponds and high-volume waterfalls — they are more powerful, easier to maintain, but require priming and weatherproof housing. Size the pump based on the desired flow rate (gallons per hour) and the head height (the vertical distance the water must be pumped). A waterfall needs approximately 100 to 150 GPH per inch of waterfall width.

Plumbing Layout

Use flexible PVC or braided PVC tubing for the water supply lines from the pump to the water feature. Size the tubing to match the pump outlet — using undersized tubing restricts flow and reduces performance. Minimize the number of elbows and fittings, as each one reduces flow. For long runs or high head heights, upsize the tubing by one increment to compensate for friction loss. Install a ball valve on the pump outlet to control flow rate without adjusting the pump speed. Use stainless steel hose clamps on all barbed fitting connections.

Filtration and Water Quality

Ponds with fish require biological and mechanical filtration to maintain water quality. A basic filtration system includes a skimmer (removes surface debris), a biological filter (houses beneficial bacteria that break down waste), and UV clarifiers (control algae). The plumbing connects the skimmer to the pump, the pump to the filter, and the filter to the waterfall or return. Plumb the system so the filter can be cleaned without draining the entire pond — include unions or quick-disconnect fittings at the filter connections. Simple decorative fountains without fish only need a screen on the pump intake to prevent debris from entering.

Winterization and Maintenance

In freezing climates, water features must be winterized to prevent pump and plumbing damage. For small fountains, drain all water, disconnect the pump, and store it indoors. For ponds, lower the water level below the skimmer inlet, disconnect and store the pump, and remove the UV clarifier. In ponds with fish, leave a de-icer or floating aerator to maintain an opening in the ice for gas exchange. Drain all supply tubing and store it loosely to prevent kinking. In spring, clean and inspect all plumbing connections before refilling and restarting the system. Replace pump impeller seals and tubing clamps annually as preventive maintenance.