Guide

How to build a natural swimming pool yourself

We built our natural pool ourselves between March 2014 and June 2015, and our family has swum in it every summer since. This is the order we did it in, plus what I'd change.

1. Plan the layout and check with your city

Decide the swim zone, the plant zone and where the pump will sit. In our city it was classed as a pond, not a pool, and no permit was needed. Your city may be different, so call before you dig and ask how they classify a pond versus a pool, and whether depth or fencing rules apply.

2. Dig

Five days on a skid steer got us most of the way. An excavator dug the deep end in a weekend. I hoped for 10 to 11 feet and stopped at 8 when we hit hardpan. Your ground may decide your depth. Keep the dirt; we used ours to raise the waterfall and build a berm.

3. Underlayment, liner and liner protector

Cover every inch of dirt so no rock can push through the liner. Lay the liner, then a thick protector over it. Anything that sits on the bottom rests on the protector, not the liner, because friction is how liners get punctured. Learn to seam on scrap first; it took me many tries to get a seam that held.

4. Build the swim zone walls

Ours is an octagonal cedar box standing inside the lined hole, on treated base and top plates resting on the protector. Geogrid laid back into the gravel holds the wall against the weight of the filter rock.

5. Plumbing before gravel

Sleeved perforated pipe goes in around the swim zone before any gravel. Ours has five runs joined into one line to the pump. Don't skip the sleeve, or grit ends up in your pump.

6. Filter rock

Truckloads of expanded shale fill the ring around the swim zone and the plant zone. It's more loads than you think.

7. Pump, UV, skimmer and waterfall

The pump pulls from the filter pipe and a skimmer, runs through a UV light, and returns over a waterfall fed from a stock tank. Put valves on every branch so you can balance the flow.

8. Fill, plant and wait

Filling took three to four days. Plant the shelves, and give it a full summer for the bacteria to colonize. Keep yard runoff out of the pond; one storm washing fertilizer in will undo a summer of work.

What I'd do differently

• Two pumps and two skimmers on a pool our size.
• Deeper plant shelves, closer to 24 inches than 10 or 12.
• A liner that's easier to weld and repair.
• Build the dock stronger than you think. Twenty people will stand on it at once.
• Never plant phragmites. Check every reed you buy.

Get your parts list

The designer turns your sketch into a full parts list sized for your pool, from liner and pipe to plants. Or start from one of 70 designs.