Natural swimming ponds may be replacing the swimming hole in a nearby creek or lake that you remember from childhood or the neighborhood swimming pool. Children and adults now swim in sterile-feeling concrete boxes with blue bottoms and tile around the sides. They run on concrete decking and rarely see plants except in pots. But since 1985 in Europe and now in the United States, it is possible to recreate that natural pond feeling in your back yard with a natural swimming pond.
I have been asked hundreds of times if clients could swim in their ponds. I advised against it because they were usually too shallow and full of bacteria. Now US companies are building natural swimming pools successfully.
A natural swimming pool will cost more at installation, but because you need no chemicals, the higher price will balance over time.
Can I do it myself?
Building a natural swimming pool in your back yard can be an arduous task for the do-it-yourselfer, but it is certainly doable.
You need a large space, larger than the pool itself because you need to have space for the natural filtration setup that is necessary. You will need either machinery to dig a hole or lots of strong backs. The hole has be be as deep as you wish to swim. If that is six feet, you have to dig a hole at least that deep. That is much digging and would most likely best be left to a professional heavy-machine operator.
You must line your hole. I would use a good underlayment before using EPDM or butyl rubber as a liner. Your liner will get lots of abuse from feet, dogs and debris, so put a good cushion under it. Old carpeting could work, as could layers and layers of newspapers. Buying an underlayment is probably your best bet.
Build a wall
Now you must wall off where you will do your swimming. You can use lumber to build a wall on top of the liner, delineating exactly where you want to swim. The top of that wall must be under the surface of the water because your filtered water needs to go over the top. Top that wall with finish lumber like 1' x 12' .
What about filtration?
In the space in back of the wall and up onto the "beach" part of your swimming pond, you will place as much large and small gravel as the space will hold. That serves as a filtration system. Your pump will pump water from the swimming part of the pool into the rocks, and the water flows back into the pool clean and clear. The pump and any other equipment necessary is hidden under the decking.
Finally, plant your new natural swimming pool. Put submerged vegetation and bog plants in the rocks. The roots will serve as natural filters and deliver nearly bacteria-free water to swim in.
Something to check on
There is one caveat to using a natural swimming pond. Check your local regulations building codes. In some states a swimming pool must be built by a licensed swimming-pool contractor who has appropriate general liability and workers' compensation insurance. A swimming pool must be of a certain depth and abide by other building codes. The worry of pond contractors is the chance of litigation if a child ends up with e.coli or salmonella.
Manufacturers of natural swimming ponds claim that the water is clear, clean and safe for swimming. When I think back to places I have been swimming as a child and adult, I would have to agree, but don't forget to follow basic water safety rules.
Mosquito fish are a great natural solution to the problem of landscape pond insects, but you'll need to take some steps to keep your fish healthy.
Pond leaks are not fun. Noticing a water level drop, you are sure you face repairing your pond liner. Before you panic, make absolutely sure it is a leaking liner and not another problem.