Good koi pond plumbing carries the required flow and lets you service equipment without dismantling the entire system. PVC is common for water circuits, but pipe size, fittings, layout, and installation quality matter more than choosing one material alone.
Separate Gravity and Pumped Circuits
A gravity-fed bottom drain relies on the difference in water level to move water toward a filter. A pump-pressure line operates differently. Do not assume the same pipe size will work for both at the same flow.
Use the drain, filter, and pump manufacturers' requirements to plan each circuit. Long runs, fittings, elevation changes, and equipment restrictions reduce delivered flow. Select a pump using its performance curve at the estimated total dynamic head.
Make Maintenance Possible
- Use suitable isolation valves where equipment must be removed.
- Include unions or appropriate removable connections at service points.
- Keep waste drains and valve handles accessible.
- Provide a safe overflow route and a controlled refill arrangement.
- Plan frost protection and drainage for exposed circuits where needed.
Assemble According to the Product Instructions
Choose water-service pipe and compatible fittings rated for the application. Cut and prepare joints carefully, and follow the specified primer, cement, working time, and cure time. Do not add fish before new plumbing has been appropriately cured, flushed, and checked.
Use a planned water leak test before concealing pipework. Do not improvise a compressed-air test of water-service PVC or use it as compressed-air storage. Follow the applicable product ratings and obtain professional help for uncertain pressure or electrical arrangements.
Keep a Plumbing Map
Photograph underground runs before backfilling. Label valves by circuit and record pipe sizes and equipment models. A simple map can save hours when a leak, winter shutdown, or pump replacement occurs.
Continue with pump sizing and the installation checklist.