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Downspout extensions, splash blocks and the Waterloo stormwater credit: what counts and what does not

A downspout extension or splash block does not qualify for the City of Waterloo's residential stormwater credit, which rewards capturing or soaking rainwater into the lot with rain barrels, cisterns, infiltration galleries, rain gardens or permeable pavers, up to 45 per cent off the stormwater fee. Extensions and splash blocks do a different job: they keep roof water off your foundation and off your neighbour, which is what the City's property standards rules ask of you.

Last updated October 24, 2026 · Reviewed by the Waterloo Gutter Cleaning team

Does a downspout extension get you a stormwater credit in Waterloo?

No. The City's stormwater credit page lists five kinds of qualifying measure, rain barrels and cisterns, infiltration galleries and similar underground pits, rain gardens and permeable pavers, and credits them by how many litres of rainwater they capture. A downspout extension moves water; it does not capture any. The same goes for a splash block, a flexible downspout hose or a downspout simply redirected onto the lawn. None of them appears on the City's list and none earns a percentage.

That does not make them pointless. They are the cheapest way to get roof water two or three metres away from the foundation, and on a Waterloo lot they are often the difference between a dry basement and a damp one in March.

What extensions and splash blocks are for

The City of Waterloo's property standards page says its by-law includes rules on directing roof drainage away from neighbouring properties, sidewalks and roadways, keeping grading so that water drains safely away from buildings and follows the neighbourhood's original drainage design, avoiding excessive ponding, and preventing water from damaging buildings or structures. A downspout that dumps at the foundation, pours across the sidewalk or runs onto the next lot is on the wrong side of all of that.

So the extension's job is simple: carry the water far enough that it lands on grass or garden on your own property, away from the wall, and does not pond. On the big lots of Beechwood and Lakeshore that is easy; there is lawn to spare. On the narrow rental lots of the university district, where the side yard is a shared strip a metre wide, it takes some thought, and a complaint about a downspout pouring onto a neighbour's walkway is a by-law matter for the landlord, not just a maintenance one. Waterloo also requires an annual rental licence for long-term rentals of a house, duplex or townhouse, which is one more reason landlords keep the drainage tidy.

The credit tiers, as the City publishes them

The City of Waterloo's residential stormwater credit is for owners of a single home or duplex, and it is calculated on the litres of rainwater the property captures:

• 200 to 500 litres: 9 per cent
• 501 to 1,000 litres: 18 per cent
• 1,001 to 2,100 litres: 27 per cent
• 2,101 to 2,260 litres: 36 per cent
• 3,361 litres and above: 45 per cent

Those are the figures as published; the City's page leaves a gap between 2,260 and 3,361 litres, so ask the City how a system in that range is treated. Measures can be combined to reach a higher tier. The practices must sit on the property and serve only that property, must not affect City infrastructure, neighbours or the environment, and if a measure stops working or is removed the credit ends. Underground controls installed by the builder as part of the original subdivision do not qualify, because they exist to meet drainage requirements the development already had to satisfy. Applications are currently taken by email or mail only, using the City's fillable residential form.

Rain barrels: the conditions people miss

A rain barrel is the measure most Waterloo homeowners start with, and the City attaches conditions that a gutter visit can check. Each barrel or cistern must hold at least 200 litres, sit on a flat and stable surface, be covered and leak-free, and have a debris screen. It must be securely connected to a downspout, and its overflow must drain to a grassed or garden area, not a driveway or other paved surface. The City's page also sets a minimum number of barrels for an application, so read it before you buy one.

Every one of those conditions depends on the downspout above the barrel running clear. A barrel fed by a downspout plugged at the top elbow captures nothing, and a trough that dumps leaves into the barrel clogs the screen within a season. That is why a downspout flush and a barrel diverter are the same job from the roof's point of view. The crew fits the diverter; the application and the approval are the City's.

Infiltration galleries and rain gardens

For a bigger credit, the City's page describes infiltration galleries, soakaway pits, dry wells and French drains: gravel-filled underground pits that downspouts are routed straight into. The City advises keeping them at least 5 metres from the house and recommends gutter guards on the troughs that feed them, because a pit that silts up with leaf compost stops draining. A rain garden has to hold a measurable volume, receive runoff directly from a hard surface such as the roof, and soak it into the soil within 72 hours. Permeable pavers need wide gaps, loose gravel rather than sand, and a 30 cm stone base.

These suit the big Beechwood and Lakeshore lots, where there is room to put a pit 5 metres out and a long roof worth of water to feed it. They suit a Laurelwood lot less well, not because the house is new but because the lot is small and the builder's grading plan already decides where water is allowed to go.

What this means for a gutter visit

Whether or not you apply for the credit, every downspout on the house should be flushed until it runs clear, and every outlet should be checked for an extension or splash block that is still attached, still pointing away from the foundation and still landing on your own grass. That check is part of every clean the contractor we book for Waterloo does, and it is the part that matters most after the snowblower has been through. If you are pursuing the credit, say so when you book, and the diverter or the guards can be fitted on the same visit. Planning ranges are on the Waterloo gutter cleaning cost page.

Sources

• Apply for a stormwater credit - City of Waterloo
• Follow property standards - City of Waterloo
• Residential rental licences - City of Waterloo