Joe and Kelly Ostrowski's koi pond in New York started as one small waterfall. Today it holds about 14,300 gallons and more than 25 big koi, and the waterfall has grown into a long stream that drops down a planted slope under the pines before it spills into the pond. Joe dug the whole thing by hand, through limestone, and the stone around the edge came from neighbors who were tearing out their old retaining walls.
We rebuilt their pond in 3D in our Pond Planner, waterfall and plants included. Skip ahead to explore it.
From a small waterfall to a koi pond
Joe's pond started with curiosity and a simple waterfall. YouTube videos and friends who kept koi got him thinking bigger, so he built a small pond, and it wasn't long before he wanted more. Each year he dug it out further and refined the design, until it became the pond they have now.
From the start, Joe kept koi. His first ones came from Kodama Koi Farm, a name serious koi keepers know. Later, when a neighbor passed away, Joe and Kelly took in eight of his koi, and those fish are now among the first to swim over and say hello.
Dug by hand and edged with reclaimed stone
Joe built the pond without machinery. Digging through limestone soil by hand was slow, backbreaking work, and he takes pride in knowing that every detail came from his own effort.
The stone came from their own neighborhood. Joe and Kelly drove around collecting truckloads of it from neighbors who were taking down old stone retaining walls, then shaped it into the pond's border and the waterfall. Under the stone is a 45 mil EPDM liner, laid over an underlayment that protects it from the rocks.
A long stream waterfall and a lot of plants
Ask Joe what he likes most and he'll tell you it's the rocks and the plants.
"The way the rocks came together, the plants growing, it just gets more beautiful."
In their photos the water starts high on the slope under the evergreens and drops through several falls on its way down, finishing with a wide fall into the pond. Joe gave the waterfall a pump of its own: a 10,000-gallon-per-hour pump that runs the falls and nothing else, fed through flexible PVC.
The banks are planted the whole way around. A red Japanese maple and ornamental grasses grow beside the stream, hostas fill in along the stone, and pickerelweed and tall reeds crowd the shallow edges. Water lilies float on the open water, and the frogs have claimed them. The plants also feed on the nutrients the fish put into the water, which is part of how Joe keeps it clear.
Want the same look? Browse our marginal water plants for the shallow shelves and bog plants for the wet ground around them.
DIY filtration for 14,300 gallons
Joe built the filtration himself as well. He repurposed two 55-gallon drums as filters and lined them with floor buffer pads that catch the waste coming out of the pond. He also built a bog filter, where plant roots clean the water naturally.
A second pump, rated at 4,500 gallons per hour, handles circulation and filtration, and a 55-watt UV clarifier keeps green water away. An air bubbler runs all year. Over time Joe added more mechanical filtration, and his next project is a filtration shed with UV sterilization.
Joe cleans the filters every day and looks after the rest of the system with real care.
A hard lesson with parasites
Like a lot of koi keepers, Joe and Kelly learned some lessons the hard way. A misstep while treating for parasites cost them their original koi collection. Joe was heartbroken, and he buried each fish by hand.
They kept at it. With guidance, better treatments and improved filtration, they built a healthier pond, and today their koi are thriving, with bright colors and big personalities.
Living with the pond
The pond is at the center of their days. In the evenings Joe and Kelly sit out on the back deck, and the koi swim up to greet them like dogs waiting at the door. Each fish has its own personality: some follow them along the edge, others wait to be fed, and the koi they adopted from their late neighbor seem especially attentive, as if saying thank you.
Wildlife found the pond too. Frogs, turtles and visiting ducks all spend time there.
Koi, lilies, frogs and the falls, from Joe and Kelly's photos.
Joe and Kelly's advice for new pond owners
- Ask questions. "If you don't know, ask," Kelly says. Fellow koi keepers and the Play It Koi team helped them through the tough moments.
- Be dedicated. A pond needs the same commitment as a pet.
- Trust DIY filtration. Their drums, buffer pads and bog filter show how far creativity and persistence can go.
- Be patient. Trial and error is part of the hobby, and every mistake leaves you knowing more.
What the pond means to them
For Joe and Kelly the pond is a sanctuary, the place where they relax, recharge and connect with nature. Friends, neighbors and even coworkers stop to admire it. When we asked what the pond means to them now, Kelly put it best:
"They're our pets. They look at us like a dog would. This is our life. I don't know if we could ever move and give this up."
Joe and Kelly's pond at a glance
- Owners: Joe and Kelly Ostrowski, New York
- Build: do-it-yourself, dug by hand through limestone and expanded year by year
- Size: about 36 feet long and 24 feet wide
- Depth: 53 inches at the deepest point
- Volume: about 14,300 gallons
- Fish: more than 25 large koi, 18 to 28 inches long
- Liner: 45 mil EPDM over a protective underlayment
- Edging: natural stone reclaimed from neighbors' retaining walls
- Waterfall: a stream with several falls, fed through flexible PVC by its own 10,000 GPH pump
- Filtration: two 55-gallon drums with floor buffer pads, a bog filter and plenty of plants, with a 4,500 GPH pump for circulation
- UV: a 55-watt UV clarifier
- Aeration: an air bubbler that runs all year
Sizing your own pond? Our guide to pond gallons and liner size walks through the math.
Plan a pond like Joe and Kelly's
Now you can walk around Joe and Kelly's pond yourself. We rebuilt it in our Pond Planner from the numbers Kelly sent us: 36 by 24 feet, 53 inches at the deepest point and about 14,300 gallons. The natural outline has a planting shelf around the edge and a deep bowl in the middle. The stream climbs 20 feet up the bank behind the pond and starts 5 feet above the water, stepping down in a string of small falls past a red Japanese maple and three pines. Iris and cattails line the shallows, water lilies float on the open water, and a wood fence runs along one side.
The shelf and the stream's length and height are our estimates from their photos. The planner can't draw a bog filter yet, and homemade drum filters aren't in our catalog, so the equipment in the plan is its own recommendation for a koi pond this size: five aerated bottom drains, three skimmers, a drum filter, a bead filter, a 480-watt UV clarifier and two pumps, all in a white pump house beside the pond. It's a bigger system than Joe runs today, and a look at what a filtration shed like the one he's planning could hold.
Planning a system like this? Our buyer's guides cover bottom drains, bead filters and UV clarifiers, with sizing and installation tips.
Open Joe and Kelly's pond in the planner to spin it around in 3D, follow the plumbing to the pump house and see every part on the list. Like what you see? Hit "Start my own pond" and design yours.