Instead of chemicals and mechanical treatment, 60,000 plants sort out sewage from the village which has a population of 750.
The reed beds are spread across five ponds in a wetland the size of five football pitches.
During the 90 days it takes for the effluent to pass through, bacteria, ultraviolet light and the plants act on it.
When that is done, the run-off can be piped straight into a local river.
It is the first natural sewage treatment works developed by Northern Ireland Water.
They call it an integrated constructed wetland and it cost just over half the price of a traditional treatment works.
NI Water began looking for a solution after the existing treatment works at Stoneyford began to fail.
It had planned to build a replacement, but then it heard about a wetland alternative at Glaslough in County Monaghan.
The next challenge was to persuade people in Stoneyford that it could work.
"The local people were saying `what are you doing, you're going to put raw sewage onto the ground, we don't want that`, said NI Water's Dermott McCurdy.
"They were thinking about furry animals, flies, smells, and I could understand that."
So NI Water bussed a delegation to County Monaghan to have a look for themselves.
Mr McCurdy said that on the way back, there was a change in their attitude.
The wetland cost Â£800,000 and began working fully this spring.
In a couple of years the reeds and other planting will have matured. It is already attracting birds and insects.
The plan is to open it as a community resource that can be used by the villagers.
One resident, Jonathan Seymour, said there was a "mixed response" at first.
"Most of us are taxpayers and actually when we look at it, we're getting value for money," he said.
"It's nice to think that the environmental option isn't the most costly option. In fact, it's probably the cheapest option here."
It is one of several now being developed around Northern Ireland, including one with a 5,000-person capacity at Ballykelly, and a smaller one at Castle Archdale in County Fermanagh.
It is not an obvious place for an evening stroll, but then the sewage treatment works in Stoneyford, County Antrim, is not your average industrial facility.