» March 8, 2024

How Landscaping Can Save You Money With A Stormwater Credit Program

Raised interlocking patio with drainage solution

You might not know it, but your city probably has a stormwater credit or rebate that you can take advantage of with water conscious landscape installations. A stormwater credit or rebate is put in place to encourage property owners to install water diversion systems on their properties. These systems capture stormwater (like rain or snow melt), and allow it to infiltrate directly into the ground, instead of collecting into the municipal catch basins and stormwater ponds. By providing an alternative outlet for some of the water on your property, the city benefits from lower stress on their own systems and may offer a credit for the capacity that you aren’t using – specifically for how much water your on-property drainage diverts. Depending on your region, these credits may be available to single or multi-residence properties in addition to non-residential properties or developments.

What Types of Water Diversion Systems Qualify for a Stormwater Credit?

Infiltration Galleries

If you’re already experiencing water problems – like standing water or flooding – then a drainage solution that includes an infiltration gallery will be your solution. Infiltration galleries generally consist of dry wells and French drains. Their purpose is to allow clean water to soak or “infiltrate” into the ground and recharge drinking water sources. They usually take the form of channels and pits that are filled with 3/4” clear stone, providing a storage space for water while it absorbs into the ground. Infiltration galleries may also be installed alongside hardscaping like patios and walls, to ensure water is appropriately redirected from these areas and avoid future issues. Below are some examples of the types of infiltration galleries that we frequently install which can be used to divert water.

A low angle photo from the middle of an interlock patio looking towards the back veranda of a home with a natural stone step and downspout tie-in

Downspout Tie-Ins:

A Downspout tie-in collects clean rainwater from rooftops and redistributes the water back into the ground in a way that avoids contamination. Downspout outlets are channeled into a PVC pipe to collect the water and carry it in a stone-filled trench away from the building and filtered back into the ground. Once the pipe is a sufficient distance from the foundation, it may be perforated, allowing water to escape from the sides and the end in a controlled manner. The trench is wrapped in a thick fabric to keep the system free of sand or soil when buried. Normally a down-spout tie-in will run under a yard or a garden, hidden beneath plants or grass. The system may be completed with a pop-up drain where it ends, that provides access to clean out the pipes, if necessary, and to relieve the drain if the system reaches capacity.

A graphic section showing how a downspout tie-in is installed

French Drains:

A French drain is a storm water management system designed to redirect water away from a specific area, like a low spot, typically to prevent water accumulation and potential damage. Similar to a downspout tie-in, a French drain is constructed as a fabric-lined trench containing a PVC pipe surrounded by clear stone. The pipe is perforated for the entirety of the drain, to facilitate efficient removal of excess water and prevent waterlogging or soil erosion. Once complete, the French drain can be covered with soil and sodded, or left day-lighted with a layer of decorative clear stone like river rock along the top for even faster infiltration. Often, the top of the French drain will be at a lower grade creating a trough to help direct water into and along it. The drain may terminate in a pop-up outlet, or a catch basin.

A graphic section showing how French drains are installed

Dry Wells:

A dry well is designed to manage excess water runoff by providing a reservoir for its temporary storage. A dry well consists of a dug pit filled with ¾” drainage stone and surrounded by a landscape fabric, allowing water to percolate into the surrounding soil gradually. Dry wells are commonly used to prevent surface flooding and soil erosion by absorbing and dispersing rainwater or storm runoff. They may be installed as part of a system with other drainage methods terminating at the dry well.

A graphic section showing how a dry well is installed

Decorative Drainage Systems

Not every drainage solution is hidden, some are integrated into the landscaping work. Both permeable pavers and rain gardens are two types of decorative drainage systems that add value to your property and qualify for stormwater credits.

A photo of an interlock patio with different kinds of pavers that all have a permeable jointing medium for drainage

Permeable Pavers

A permeable paver is an interlocking paving stone that allows stormwater to percolate and filter through the stones when laid, and into the aggregate base layers below, eventually making its way into the soil. Permeable pavement surfaces are made of nonporous (solid) and porous (allowing water to move through) materials which allows the water to flow between the gaps. Permeable pavers reduce runoff and improve water quality by filtering pollutants in the subsurface layers. Installing a permeable patio is a great way to extend your outdoor living space and get a return on your investment.

Rain Gardens

A rain garden is built with the specific intention of holding excess water and filtering it into the ground. It is created in a shallow depression that collects the water and holds it while it infiltrates into the ground, rather than becoming runoff. The gardens typically include plants that thrive in both wet and dry conditions. Often, the selected plants will also be salt-tolerant if the collected water has the potential to carry salt from hard surfaces in the winter.

A rain garden should have the following infiltration properties:

  •       a quantifiable volume of water must be held on your property.
  •       water from impervious surfaces such as rooftops must be routed directly to the garden.
  •       water should soak into the soil within 72 hours of a rainfall event.

A graphic section showing how a rain garden is installed

If you have a future landscaping project in mind, including a stormwater diversion system will not only help avoid drainage issues, but can reduce your municipal bills. Your city’s stormwater credit program may have some build standards that need to be met in order for your project to qualify. Check your municipal website to see what resources can be found, and who to reach out to with questions. Greenway services primarily Waterloo and Kitchener, and we have researched their stormwater credit programs to ensure our installation practices comply. You can find some further details about both programs at the links below

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