Pond construction
overview.

§01 — A typical residential build.

A residential outdoor pond consists of a small set of recurring components, assembled in a recognisable order. This article describes the components themselves; build sequencing varies by installation and is documented in any liner manufacturer's installation guide.

The components, in the order they are usually installed:

1. Excavation — a hole shaped to the desired pond profile, with shelves at appropriate depths for marginal-zone planting if the pond hosts plants.
2. Underlayment — a non-woven geotextile fabric protecting the liner from puncture by rocks or roots.
3. Liner — a flexible waterproof membrane (EPDM, RPE, PVC) or a preformed shell.
4. Plumbing — intake and return lines, typically rigid PVC.
5. Skimmer / intake bay — a niche or moulded chamber drawing surface water through a debris basket and into the pump intake.
6. Pump — submersible or external, sized to the pond volume.
7. Filter — gravity-fed, pressurised, or all-in-one canister.
8. UV clarifier — optional, plumbed downstream of the filter.
9. Return — a waterfall weir, spillway, or in-pond return diffuser.
10. Edging — stone, paver, or planted edge stabilising the liner perimeter.

§02 — Skimmer-fed vs gravity-fed.

Two plumbing configurations dominate residential ponds:

• Skimmer-fed. A skimmer at the pond edge collects surface debris in a basket and feeds the pump intake directly. The pump pushes water through a pressurised filter and back to the pond via a waterfall weir. This configuration is typical of smaller water-garden builds.
• Gravity-fed. A bottom drain at the pond's deepest point feeds a gravity-flow filter box at pond level. The pump sits after the filter, returning filtered water uphill to the pond. This configuration is typical of larger koi-focused ponds.

Pump and filter selection follow from the configuration, not the other way around.

§03 — Plumbing and fittings.

Pond plumbing uses rigid PVC in nominal pipe sizes — 1.5 inch and 2 inch are the residential standards. Hose-barb fittings on filter and pump bodies allow connection to flexible reinforced tubing (Big-O or kink-resistant pond hose) when rigid plumbing would be impractical.

Common inline fittings include:

• Ball valves — to isolate sections for maintenance.
• Check valves — to prevent backflow when pumps are off.
• Tees — to split flow between multiple returns.
• Bulkhead fittings — to pass plumbing through the liner at bottom-drain or return-diffuser locations.

§04 — Electrical.

Pond electrical follows the residential outdoor electrical code in the installer's jurisdiction. In the United States, the National Electrical Code requires pond pumps and other submersible equipment to be on a GFCI-protected circuit. Manufacturer documentation reproduces this requirement on every grounded-cord pump and clarifier.

§05 — What this article does not cover.

This article describes equipment and structural components. It does not cover stocking decisions, water chemistry adjustment, seasonal feeding practice, or any aspect of fish keeping. Those are not equipment topics and are out of scope for this catalog.