Conservation Authority Permits in Ontario: Building Near a Creek
If your property is near a creek, river, valley, wetland or shoreline in Ontario, you may need a permit from your conservation authority before you build, grade, or place or remove fill, even if the City doesn't require a building permit. Since April 1, 2024, these permits fall under Ontario Regulation 41/24, and in London most properties are regulated by the Upper Thames River Conservation Authority (UTRCA), with parts of south London under Kettle Creek.
Many homeowners only find out about conservation authority rules after a neighbour complains or a contractor stops work. Planning a winter or spring project now, whether it's an addition, a pool removal, a retaining wall or regrading a backyard that backs onto a creek, is the right time to check. Here is what the rules cover, how to find out if your lot is regulated, and how the process works.
What Ontario Regulation 41/24 covers
Ontario Regulation 41/24 (Prohibited Activities, Exemptions and Permits) replaced the older individual regulations for each conservation authority. It applies across Ontario under section 28 of the Conservation Authorities Act. In regulated areas, you need a permit for:
Development, which includes building or placing a structure, enlarging a building or changing its use, site grading, and placing, dumping or removing fill or other material.
Changing a watercourse: straightening, diverting or interfering with a river, creek, stream or watercourse.
Interfering with a wetland.
Regulated areas include river and stream valleys, hazardous lands such as floodplains and unstable slopes, wetlands, and land within 30 m of a wetland. The UTRCA regulations page explains how this applies in the Upper Thames watershed.
Which conservation authority covers your property?
Most of London: Upper Thames River Conservation Authority (UTRCA)
Parts of south London, St. Thomas: Kettle Creek Conservation Authority (KCCA)
Strathroy-Caradoc: St. Clair Region CA and Lower Thames Valley CA
Grand Bend, Bayfield area: Ausable Bayfield Conservation Authority (ABCA)
Goderich, Kincardine area: Maitland Valley CA and Saugeen Valley CA (confirm by address)
A change is coming. Ontario is consolidating its 36 conservation authorities into larger regional authorities. UTRCA, Lower Thames Valley, St. Clair Region and Essex Region are planned to become a Western Lake Erie regional authority, with the change expected in early 2027. UTRCA says permitting continues during the transition, so a permit you apply for now will still be processed.
How to check if your lot is regulated
Use the online map. UTRCA has a mapping tool at maps.thamesriver.on.ca that shows the approximate regulated area. Other authorities have similar maps.
Ask for a property inquiry. If the map is unclear, the conservation authority can confirm in writing whether your lot is regulated. UTRCA charges a fee for written property inquiries.
Look for clues. If your lot backs onto a creek, ravine, wooded valley, municipal drain, wetland or the Lake Huron or Lake Erie shoreline, assume you should check.
Common projects that may need a permit
Additions, garages, decks and sheds in a regulated area. Some small structures are exempt; see below.
Pool removal and fill-in near a creek or valley, because you're placing fill.
Regrading a backyard or building up low spots.
New or rebuilt retaining walls on a valley slope.
Driveways, culverts and crossings over a ditch or creek.
Shoreline protection and stairs on bluffs along Lake Huron.
Exemptions you should know about
Section 5 of the regulation exempts some low-risk activities. Examples include seasonal or floating docks, certain fences, and non-habitable accessory buildings of 15 m² or less, along with a few others. The exemptions have conditions, and UTRCA recommends confirming in writing that your project qualifies before you start. Don't assume a shed or patio is exempt because it is small.
The permit process, step by step
Here is how the process generally works with UTRCA:
Pre-consultation. Talk to the conservation authority before you apply. They must offer one if you ask, and it often saves a resubmission.
Submit a complete application. Include drawings, a site plan showing the creek or slope, grading details, and erosion and sediment control measures.
Completeness notice. The authority tells you within 21 days whether the application is complete.
Decision. For a complete application, the regulation targets a decision within 30 days for minor projects and 90 days for major ones.
Permit issued. Permits can be valid for up to 60 months, with conditions you must follow during construction.
UTRCA publishes a fee schedule that sorts permits into routine, minor and major categories. Check the current UTRCA fee schedule when budgeting. Other conservation authorities set their own fees.
How this fits with City permits and other rules
A conservation authority permit is separate from a municipal building permit. You may need one, the other, or both. On a typical excavation project, you should also plan for:
Ontario One Call locates before any digging. Our excavation checklist walks through locates and excess soil rules.
Lot grading. London asks homeowners to request their approved lot grading plan before changing grades. See our guide to lot grading in London.
Excess soil. Under Ontario Regulation 406/19, larger projects have soil tracking and registry requirements. New limits on landfilling cleaner soil start January 1, 2027.
Tree by-laws. Removing a large tree may need a City permit. See tree pruning and removal by-laws in London.
Erosion and sediment control basics
Most permits near a watercourse come with conditions about keeping soil out of the water. Even when a permit isn't needed, these steps protect the creek and your property:
Silt fence installed along the downhill edge of the work area before digging starts.
Stockpiles placed away from the creek and the top of the bank, and covered if they'll sit for more than a few days.
Minimal disturbance. Strip only the area you need, and keep existing vegetation on the slope.
Quick cover. Restore disturbed ground with topsoil and sod or seed as soon as grading is done.
No work in the water unless your permit allows it.
Permit checklist for creekside projects
☐ Checked the CA map for my address
☐ Requested a written property inquiry if the map is unclear
☐ Booked a pre-consultation
☐ Site plan showing the creek, top of bank and the work area
☐ Erosion and sediment control plan (silt fence, stockpile location)
☐ Municipal building or site alteration permit, if required
☐ Ontario One Call locate booked
☐ Contractor with WSIB coverage and liability insurance
Why winter is the time to apply
Excavation and grading crews get busy as soon as the ground thaws. Decision timelines can run up to 90 days for major applications, so applying in late fall or winter means a spring project can start on time. Late-fall and winter work is possible on some sites. Our post on late-fall and winter excavation explains what can still get done.
FAQ
Do I need a conservation authority permit to regrade my backyard?
If your property is in a regulated area, yes. Under Ontario Regulation 41/24, site grading and placing or removing fill count as development and need a permit. Check your conservation authority's map or ask for a property inquiry.
Which conservation authority covers London, Ontario?
Most of London is in the Upper Thames River Conservation Authority's watershed. Parts of south London fall under the Kettle Creek Conservation Authority. Check by address with either authority.
How long does a UTRCA permit take?
After an application is complete, the regulation targets a decision within 30 days for minor applications and 90 days for major ones. UTRCA confirms whether an application is complete within 21 days.
Is a small shed near a creek exempt?
Some non-habitable accessory buildings of 15 m² or less are exempt under section 5 of the regulation, but conditions apply. Confirm in writing with your conservation authority before you build.
Will the conservation authority mergers affect my permit?
Ontario plans to consolidate conservation authorities, with the western regional authority expected in early 2027. UTRCA says permitting continues uninterrupted during the transition.
Plan your project with an experienced local crew
SPM Landscape & Excavation has worked on residential and commercial sites across London and southwestern Ontario since 2006. We are WSIB covered and carry $1 million in liability insurance, and we can work with your permit conditions, including silt fencing, stockpile placement and final grading. Call (519) 474-0008 or email spmlandscape@gmail.com.
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