Skip to main content

Kevin Mercer, who launched RainGrid with engineer Stephen Braun, says their barrel system handles residential stormwater at its source, before it becomes a problem. ‘We reduce the infrastructure cost to the city, the downstream damage and the pollution.’

Galit Rodan/The Globe and Mail

Innovators at Work is a contest to recognize talented people who not only have great ideas but also turn them into reality through their drive and their actions. You can nominate an Innovator here.

In heavy rain, the plink-plonk of water dripping in a storm barrel by the side of the house is evocative, poetic. The splash of dirty flood water on a residential street isn't.

Environmentalist Kevin Mercer and engineer Stephen Braun have started a company to make that rain barrel prevent roadway flooding. And in the process, by linking the operation of residential rain barrels, the company aims to change stormwater management systems for entire communities and cities.

Story continues below advertisement

Their Toronto-based RainGrid sells storm barrels which connect wirelessly to other barrels around a neighbourhood through a central computer server. Before rainfall, the residential barrels, with special valves, release their stores of water into the ground. Emptying the barrels allows them to be more effective during the next rain and prevents the sudden runoff of water and flash flooding that occurs during a storm.

It's a simple idea, but the trick was to empty the barrels en masse.

"We're taking a formerly passive, unmanageable system which is the residential rain barrel – which is sold as a consumer good – and converting it into a smart grid utility," Mr. Mercer said. "We want that utility to serve as the first line of defence in stormwater."

The barrels and control system would be owned by cities, in what Mr. Mercer and Mr. Braun see as a public-private partnership with RainGrid. Already they are the sole suppliers of this technology to Washington, D.C., providing 1,000 barrels a year.

Mr. Mercer's background is in environmental advocacy, and he has been heavily involved in programs to stop runoff into urban rivers through the not-for-profit organization RiverSides. His business partner Mr. Braun comes from the world of water-systems engineering.

Stormwater damage is the largest source of insurance claims, the two explained, as they sat in their office in an old municipal waterworks repair shop hidden in Toronto's trendy downtown westside. The devastating Alberta floods and the two once-in-a-hundred-year storms in Toronto last year were a wake-up call, Mr. Mercer said. The old solution for cities to build ever larger pipes and larger water infrastructure to divert stormwater isn't working in an age of climate change.

Like rooftop solar panels and home recycling bins, the solution is to address the problem at the source, he said. "Right now we have an end-of-the-pipe ethos."

Story continues below advertisement

RainGrid's network of co-ordinated rain barrels at every house would, instead, "treat rain where it falls. We take it off roofs. We store it on the properties. We reduce the infrastructure cost to the city, the downstream damage and the pollution to the environment."

Rather than an extra expense for taxpayers, Mr. Mercer and Mr. Braun said that a co-ordinated rain barrel system would cost significantly less than expanding water systems– this at a time when many municipalities are considering raising fees or taxes for stormwater management. Mr. Mercer and Mr. Braun see their technology helping to offset those costs.

The company has revenue of $250,000 annually. The partners expect this to increase to $5-million a year within three years, as they look to get another two or three major cities on board with the project. They foresee other companies will start adopting and offering this service to other cities, as the stormwater problems worsen in municipalities. There's only so much one company can handle, and others will follow, Mr. Mercer indicated.

"We estimate that every city will have rain grids of some kind or another," Mr. Mercer said. "We are building the system that will make cities stormwater-resilient."

Report an error Editorial code of conduct Licensing Options
As of December 20, 2017, we have temporarily removed commenting from our articles. We hope to have this resolved by the end of January 2018. Thank you for your patience. If you are looking to give feedback on our new site, please send it along to If you want to write a letter to the editor, please forward to