You have a lot in Longueuil, or you're thinking of buying one. The big question: can we really build on it?
It's not always easy. Even if you've been paying property taxes for years, that doesn't guarantee anything. In 2024-2025, the City of Longueuil tightened its urban planning regulations. Residential building permits exploded by 339 %, but at the same time, about 10 % of land was reclassified as protection or conservation zones.
This means that before dreaming about your future home or income-generating project, you need to check out a number of things. Zoning, flood risks, soil quality, easements... It's a bit like a jigsaw puzzle where all the pieces have to fit together..
In this guide, we explain exactly how to find out if your land is suitable for building. No complicated jargon, just clear steps to avoid unpleasant surprises and permit refusals.
The essential criteria for building land in Longueuil
It's not just a question of «I've got an empty lot, so I can build». Constructability depends on three main criteria: zoning and municipal by-laws, the physical constraints of the land, and environmental or legal risks.
We'll look at each of these elements in detail.
Understanding zoning (Master Plan + by-laws CO-2024-1285/1286)
Zoning is rule number one. It determines what you're allowed to do with your land.
In Longueuil, each lot is classified into a specific zone: residential, commercial, agricultural, conservation or mixed. Zoning by-law CO-2024-1286 defines for each zone the permitted use, maximum density (number of dwellings per hectare), building height, and even the type of construction allowed.
For example, a lot zoned «Low-Density Residential» might allow a single-family home, but not a duplex or triplex. In some zones, height is limited to two storeys. In others, you must respect a minimum lot size, say 500 m² minimum.
In 2025, some 10 % of land in Longueuil was reclassified as an environmental protection or conservation zone. This mainly affects areas near wetlands, woodlands or watercourses. If your land falls into one of these zones, your chances of building are slim to none.
How to check zoning with Infolot + Rôle foncier
The good news is that it's easy to check. The City of Longueuil offers a free online tool called Infolot.
Go to the «Online services» section of the city's website, then «Infolot». Enter your address or cadastral lot number. You'll see a sheet showing the exact zoning, authorized use, minimum lot dimensions and applicable bylaws (such as CO-2024-1286 or VL-2025-839).
The land roll, also available online, gives you additional information: land value, surface area, and sometimes notes on easements or restrictions.
This is your starting point. If the zoning is correct and residential use is permitted, you can move on to the next step. If not, you may need to apply for a minor variance or zoning change, which can take months and is never guaranteed.
RBQ standards, drainage and technical constraints
Even if the zoning is good, it's not enough. There's a myth going around: «If it's zoned residential, I can build.» Not true.
Approximately 30 % of construction projects in Québec are blocked or delayed due to technical standards set by the Régie du bâtiment du Québec (RBQ).. These standards cover structure, insulation, ventilation, drainage and safety.
A case in point: the French drain. In the Montérégie region, clay soils are common. If your property has a high water table or poorly permeable soil, you'll need to install a drainage system that complies with RBQ standards. This can add several thousand dollars to the project.
The bearing capacity of the soil is another matter. If the soil is unstable, poorly compacted or clayey, you may need to reinforce it or choose a specific type of foundation. A geotechnical study costs between 500 $ and 2,000 $, but it can save you a lot of trouble later on.
And then there are the issues of access to services: water, sewage and electricity. If your land is landlocked or far from infrastructure, you may have to pay to extend services, which can cost 20,000 $ or more.
Risk zones: flooding, contamination, easements
Longueuil is close to the St. Lawrence River. Some 20 % of land in Longueuil is affected by flood zones or wetland constraints.
The Quebec government has an interactive map of flood-prone areas. You can consult it on the Ministère de l'Environnement website. If your property is in a 0-20 year or 20-100 year flood zone, construction is either prohibited or highly restricted. In some cases, you'll have to raise your house or install costly mitigation measures.
Then there's soil contamination. According to provincial data, around 15 % of land in Quebec has traces of contamination, mainly in former industrial or agricultural areas. In Longueuil, certain areas such as Vieux-Longueuil or near old railroad lines may be affected.
A Phase I environmental assessment costs between 1,500 $ and 5,000 $. If the land is contaminated, it must be decontaminated before construction, which can cost tens of thousands of dollars.
And then there are servitudes. A servitude is a right that another person or organization (such as Hydro-Québec or the City) has over your land. It can limit or prevent construction. You can check this at the Index des immeubles du Québec (registry office).
Need a complete diagnostic for your land in Longueuil? Request a constructability analysis with Cartago Construction.
Step-by-step verification: how to analyze a plot of land before buying or building
Now that we know the criteria, let's see how to do the check in the right order.
It's a four-step process. Each one is important. If you skip a step, you risk losing time, money, or ending up with a permit refusal.
Step 1. Check legal feasibility (zoning, regulations, usage)
Start with zoning, as mentioned above. Use Infolot to confirm the permitted use.
Next, consult by-law CO-2024-1286, Longueuil's main zoning by-law. You can find it on the City's website, in the «By-laws and policies» section. This by-law is responsible for 90 % of zoning-related permit refusals.
Also check whether your land is affected by the new densification or natural environment protection measures. In 2025, the city adopted measures to protect woodlands and wetlands, changing the rules of the game for many property owners.
If you find anything unclear or contradictory, call the Service de l'urbanisme de Longueuil. They can give you a free preliminary opinion over the phone. It's not official, but it gives you a good idea.
Step 2. Analyze the site (geotechnics, topography)
If the zoning is correct, we now need to look at the physical aspects of the land.
A geotechnical study is a must. It costs between 500 $ and 2,000 $, depending on the size and complexity of the site. The engineer will take soil samples, analyze bearing capacity, check the water table, and tell you what type of foundation is recommended.
In the Montérégie region, clay soils are common. If you build on clay without analyzing it, you risk differential settlement, cracking or worse.
There's also the topography. If your site is on a slope, you may need to do some terracing, backfilling or install retaining walls. This can add between 5,000 $ and 20,000 $ to the budget, depending on the slope.
And if the land is wooded, you'll need to budget for clearing and grubbing. Count 1,000 $ to 5,000 $ depending on tree density. Warning: in Longueuil, certain mature trees are protected by bylaw. You can't just cut anything without a permit.
Step 3. Risk assessment (flooding, wetlands, expropriation)
We mentioned it above, but it's so important that it deserves its own stage.
Check the flood zone map. If you're in a constraint zone, find out about possible mitigation measures. Sometimes it's possible, but only under strict conditions.
For wetlands, consult the Ministère des Forêts' ecoforestry map. If your lot touches a wetland, construction may be refused, or you'll have to do an environmental impact study. It's time-consuming and expensive.
And then there's the question of expropriation. In 2025, the City of Longueuil updated its Schéma d'aménagement, raising debates about the potential expropriation of certain lands to create parks or protect natural areas. On Reddit, a Longueuil family recounted having paid taxes for 40 years on land they thought could be built on, only to learn that it was to be reclassified as a conservation zone.
It's rare, but it happens. It's best to check with the city to see if your land is involved in a future project.
Step 4. Request a municipal pre-analysis
Once you've done your homework, it's time to officially contact the City.
Request a pre-analysis of your project. This service is offered by the Urban Planning Department. You submit a preliminary file with your plans, lot number, project description and all relevant documentation (geotechnical study, certificate of location, etc.).
Current lead times in Longueuil are around 3 to 6 months to obtain a preliminary opinion, depending on the complexity of the project. In 2025, the city launched an initiative to reduce delays: in the third quarter, permit approvals increased by 20 % thanks to accelerated processes.
Pre-analysis is important because it gives you an official answer. If the city sees a problem, you'll know before you invest tens of thousands of dollars in plans and permits.
Want to avoid rejections and delays? Get a free estimate for your project in Longueuil with Cartago Construction.
Market data 2024-2025: what owners need to know before investing
Let's talk numbers. The market for land in Longueuil and on the South Shore has changed considerably in recent years.
Understanding trends helps you make an informed decision, especially if you're buying land to invest in or build an income home.
Building lot prices in Longueuil (2025)
In 2025, building lot prices in Longueuil will vary enormously by sector and zoning.
For an average-sized residential lot (around 500 to 700 m²) in a good area like Saint-Hubert or Vieux-Longueuil, expect to pay between 150,000 $ and 300,000 $. In more remote or constrained areas, prices can start at 39,900 $ for small lots, but here, beware: if it's too good to be true, there's probably a problem with zoning, soil, or environmental risk.
Lots on the outskirts of Brossard or near Greenfield Park are often more expensive because of their proximity to services and schools. Those near the river or in protected areas are either unmarketable or at a reduced price, but not buildable.
Price variation also depends on zoning. A lot zoned for multi-family housing may be worth two or three times more than a single-family lot of the same size, because the income potential is higher.
Explosion in permits (+339 %) and impact on buyers
In 2024, the City of Longueuil issued $250 million in residential building permits, an increase of 339 % over previous years.
This explosion is due to several factors: densification encouraged by the provincial government, strong demand for housing on the South Shore, and multi-dwelling projects that were quickly approved.
In Quebec, some 45,478 residential units were authorized in 2024. The Montérégie accounted for around 15 % of these authorizations. Multi-residential units (duplexes, triplexes, buildings with 4 or more units) grew by 55 % over the previous year.
For land buyers, this means two things. On the one hand, demand is strong, so good building land sells fast. On the other, competition is fierce, and prices are rising.
But beware: this explosion in permits does not mean that all land is automatically suitable for construction. Many of these permits concern densification projects on already-developed land (demolition-reconstruction, addition of storeys, subdivision of existing lots).
Trends in 2025: eco-construction, densification, environmental protection
The trends for 2025 are clear: eco-construction and environmental protection are becoming increasingly important.
Some 15 % of new construction projects in Longueuil incorporate eco-responsible criteria: LEED certifications, passive houses, geothermal energy, green roofs, recycled materials. The city even offers financial incentives for certain types of green projects.
But at the same time, protection of the natural environment has intensified. As we said, 10 % of land was reclassified as conservation zones in 2025. This mainly concerns areas with mature woodlands, wetlands or ecological corridors.
For homeowners, this means even more vigilance before buying. A plot of land that was constructible in 2020 may no longer be so in 2025 if the regulations have changed.
Common myths about buildability (and the 2025 reality)
There are a lot of misconceptions out there. Let's find out what's real and what's not.
Myth 1: «I pay taxes, so I have the right to build».»
This is the most common myth, and it's completely false.
Paying property taxes means you own land. It doesn't mean you automatically have the right to build on it. The right to build depends on zoning, regulations and environmental constraints.
As mentioned, there are real-life cases in Longueuil where owners have paid taxes for decades on land they thought could be built on, only to discover that the land was in a conservation zone or targeted for future expropriation.
If you find yourself in this situation, you can contest or claim compensation, but it's time-consuming, complicated and not always successful.
Myth 2: «Land in the suburbs poses no environmental risk».»
Many people think that contamination risks only apply to urban land or former industrial zones. Not true.
Some 15 % of land in Quebec has traces of contamination, and that includes the suburbs. Old dumps, abandoned gas stations, farmland with accumulated pesticides... all these can make land unfit for construction without decontamination.
In Longueuil, certain areas such as Vieux-Longueuil or near the old railroad tracks have an industrial history. Before buying, always ask for a property history and, if possible, a Phase I environmental assessment.
Myth 3: «Residential zoning guarantees permit approval».»
No. Zoning is just part of the equation.
Around 30 % of projects in Quebec are blocked or delayed due to RBQ standards, drainage constraints, insufficient soil studies, or problems accessing services.
You may have the right zoning, but if the soil is clayey, if you're in a flood zone, if you lack sewer access, or if you have an easement that crosses the lot, your permit may be denied.
That's why you need to do all the checking before you start.
Do you have doubts about the constructability of your land? Request a full audit with Cartago Construction.
How a general contractor can validate constructability for you
It's possible to do all these checks on your own. But it's time-consuming, technical and stressful.
That's where an experienced general contractor like Cartago Construction can help. We know Longueuil bylaws by heart, we have the contacts at the City, and we know exactly what to check to avoid unpleasant surprises.
What a professional immediately analyzes
When you call Cartago Construction to evaluate a property, here's what we look at right from the start:
- Zoning. We check Infolot, read the applicable regulations, make sure that residential use is permitted and that there are no hidden restrictions.
- The floor. We recommend a geotechnical study if it hasn't already been carried out. We look at the bearing capacity, the water table and the type of soil. If it's clay, we know which foundations to choose.
- Access to services. We check whether water, sewer and electricity services are available. If not, we estimate the cost of extending services.
- Drainage. We assess the slope and water flow, and determine whether a French drain or earthworks will be required.
- Easements. We consult the Building Index to see if there are any servitudes restricting construction. Hydro-Québec, Bell, the City... all of these can have an impact.
It's a complete evaluation. It gives you a clear picture before you invest.
Why work with a local expert (Longueuil / South Shore)
The South Shore is not the same as Laval or the North Shore. Each city has its own rules, its own particularities, its own challenges.
In Longueuil, we know areas like Vieux-Longueuil, Saint-Hubert, Greenfield Park, Saint-Lambert and Brossard. We know where the soil is clayey, where there's a risk of flooding, and where regulations are stricter.
We regularly work with customers buying land to build their family home, or to develop income-generating projects (duplex, triplex). We know exactly what to say to the city, what documents to prepare, and how to maximize your chances of rapid approval.
Many owners feel lost in the paperwork: Infolot, Building Index, by-laws CO-2024-1286, geotechnical studies, certificates of location... It's normal. That's why we're here.
Assessment process at Cartago Construction
When you contact us to evaluate your property, here's how it works.
- Step 1: Site inspection. We visit the site with you. We look at the topography, the access, the trees, the neighbors, everything that could influence the construction.
- Step 2: Verification of municipal documents. We consult Infolot, the land roll and the Building Index. We retrieve the certificate of location if you have it, otherwise we help you obtain it.
- Step 3: Study recommendations. If necessary, we can put you in touch with our partners for geotechnical studies, environmental assessments or topographical surveys. We coordinate everything.
- Step 4: Pre-budget and RBQ plan. We prepare a detailed pre-budget for your project. We tell you how much it will cost to build, including hidden costs (earthworks, drainage, access to services). We'll also provide you with an RBQ-compliant plan.
At the end of the process, you know exactly where you stand. You have a clear «yes» or «no», and if it's yes, you have an action plan for moving forward quickly.
Need an RBQ-compliant evaluation before you build? Contact Cartago Construction today.
Why choose Cartago Construction to validate your land and launch your project?
Cartago Construction isn't just a construction company. It's a team that knows the South Shore, understands the challenges homeowners face, and is with you every step of the way.
Local expertise + RBQ certified
We're RBQ-certified and insured. That's the basics. But what sets us apart is our local expertise.
Yassine Troudi, founder of Cartago Construction, has over 10 years' experience in residential construction in Quebec. He knows the regulations, standards and particularities of Longueuil and Montérégie.
We've worked on projects in all areas of the South Shore: Vieux-Longueuil, Saint-Hubert, Brossard, Saint-Lambert, Greenfield Park. We know where to be cautious, where approvals are faster, and where costs can escalate.
Transparency and comprehensive support (from audit to permit)
At Cartago Construction, we believe in total transparency.
We give you an honest picture of your property. If we see a problem, we tell you right away. No false promises, no dream sales. Just reality.
And we're with you every step of the way: checking constructability, preparing the file for the city, applying for permits, coordinating subcontractors, construction, finishing touches. You have a single point of contact from start to finish.
It's a turnkey service. You don't have to juggle 10 different suppliers. We take care of everything.
Reducing risk and optimizing lead times
We all know that time is money. The longer your project takes, the more it costs.
Thanks to our experience with the City of Longueuil, we know how to prepare a solid file to maximize the chances of rapid approval. We know the planning officers, we know what documents they want to see, and we know how to answer their questions.
This reduces the number of return trips, refusals and delays. On average, our customers obtain their permits 20 to 30 % faster than if they had gone through a standard process without support.
Customized studies and recommendations based on 2025 regulations
Regulations change fast. What was true in 2023 may no longer be true in 2025.
We keep up to date on all the new regulations: CO-2024-1286, VL-2025-839, new environmental protection standards, eco-construction incentives. Our advice is based on today's rules, not those of two years ago.
And we personalize our recommendations. Your project is not the same as the neighbor's. We tailor our advice to your budget, your needs and your land.
Ready to validate your lot and launch your project with confidence? Schedule your free land evaluation in Longueuil with Cartago Construction.
FAQ. Verification of constructability in Longueuil (2025)
Here are the questions we're asked most often. If you can't find your answer here, give us a call: we'll be happy to help.
How can I check the exact zoning of a lot in Longueuil?
Use the Infolot tool on the Ville de Longueuil website. Enter your address or cadastral lot number, and you'll see the zoning, permitted use and applicable bylaws. It's free and available online 24/7.
How much does a constructability study cost in Quebec?
It depends on what you include. A geotechnical study costs between 500 $ and 2,000 $. A Phase I environmental assessment, between 1,500 $ and 5,000 $. A topographical survey, between 800 $ and 2,500 $. If you use a general contractor like Cartago Construction, the preliminary constructability assessment is often free or included in the service.
How do you know if a plot of land is in a flood zone?
Consult the interactive flood zone map on the Ministère de l'Environnement du Québec website. Enter your address and you'll see whether your property is in a 0-20-year, 20-100-year or out-of-zone flood zone. You can also request a recent certificate of location, which indicates environmental constraints.
Is it possible to build on agricultural or protected land?
Generally speaking, no. Land in agricultural zones is protected by the Act respecting the preservation of agricultural land and agricultural activities. You can request a derogation from the Commission de protection du territoire agricole (CPTAQ), but this is rare and highly regulated. For land in conservation or protected zones, construction is prohibited, with very limited exceptions.
What municipal documents are required for a permit?
To apply for a building permit in Longueuil, you'll need: signed and sealed architectural plans, recent certificate of location, completed permit application form, proof of ownership, geotechnical study (if required), environmental impact study (if applicable), and payment of permit fees. Cartago Construction can help you prepare all this.
How long does it currently take to obtain a permit in Longueuil?
In 2025, timescales vary between 3 and 6 months for a residential building permit, depending on the complexity of the project and the workload at the Urban Planning Department. The City has implemented initiatives to speed up the process, and approvals increased by 20% in the third quarter of 2025.
What risks can prevent construction?
The main risks: non-conforming zoning, flood zones, contaminated soil, wetlands, restrictive servitudes, lack of access to municipal services, unstable soil (clay), steep slopes, protected trees, and future expropriation. Each risk can be verified prior to purchase.
How to read an Infolot / cadastre file?
The Infolot sheet shows you: the cadastral lot number, the zoning (e.g. «Low-density residential»), the permitted use (single-family, duplex, etc.), the minimum lot area required, the maximum authorized height, the mandatory setbacks, and the applicable bylaws (CO-2024-1286, etc.). If it's not clear, call the Urban Planning Department or contact us.
What's the difference between «vacant land» and «building land»?
«Vacant land» just means there's no building on it. It doesn't mean you can build on it. «Buildable land» means that the land meets all the legal, physical and environmental conditions required for construction. Land may be vacant but not buildable because of zoning, risks or technical constraints.
Can an easement block a residential project?
Yes, depending on the type of servitude. A servitude de passage or a Hydro-Québec easement may limit where you can build on the lot. In some cases, the servitude covers a large part of the lot, making construction impossible. Always check servitudes at the Index des immeubles before buying.
Validating the constructability of a plot of land in Longueuil isn't rocket science, but it does require some rigor. If you follow the steps in this guide, you'll avoid most problems.
But if you'd rather have peace of mind and the support of professionals who know the South Shore inside out, Cartago Construction is there for you.
We offer you a free, no-obligation evaluation of your land. We'll tell you clearly if it's buildable, how much it will cost, and how we can help you realize your project.
Call us on 438-932-4326 or write to us at info@cartagoconstruction.ca. Our office is located at 2580 Rue Cartier, Longueuil.
Your future project starts here.
