Basement Waterproofing for Markham Homes
Leaquida provides basement waterproofing in Markham — in Thornhill, Unionville, Markham Village, Milliken, Middlefield, Cornell, Berczy and Wismer. We are a licensed GTA contractor with our own crew.
Our waterproofing services in Markham cover the whole job: a free inspection, exterior or interior waterproofing, new weeping tile, sump pumps, backwater valves, window wells and foundation crack repair — one written quote, one crew, one written warranty.
Markham’s Private Plumbing Protection Rebate is one of the most generous in York Region, but it needs City approval and a building permit before the work — and it has a deadline. We plan the job around those steps.
Markham Basement Waterproofing at a Glance
| Question | Short answer |
|---|---|
| What does it cost? | Interior $50–$120 per linear foot, exterior $100–$250 per linear foot; most full projects $3,000–$35,000. Inspection and quote are free. |
| Is there a rebate? | Yes — the City of Markham rebate pays up to $5,000 to disconnect weeping tile and install a sump pump, and up to $1,750–$2,000 for a backwater valve. |
| Do I need a permit? | Yes — a building permit and City approval are needed before installation, followed by inspections. The building permit deadline is April 30, 2027. |
| How long does it take? | Crack repair and sump pumps usually take one visit; interior systems 2–5 days; exterior waterproofing 3–7 days. |
| Which method is right? | Exterior when water comes through the walls and the outside is reachable; interior for floor–wall joint leaks, high groundwater and tight side yards. |
Why Markham Basements Take on Water
Markham is drained by the Rouge River and its tributaries, with German Mills Creek and the Don in the west. Clay soils and older sewer connections in some areas add to the risk.
Rouge River system
The Rouge River, Bruce Creek, Berczy Creek and their branches cross Markham and keep groundwater high near the valleys.
Clay soils
Much of Markham sits on clay-rich soil that drains slowly and holds water against foundation walls.
Weeping tile to sanitary
In some older areas weeping tile is tied to the sanitary sewer — exactly what the City rebate pays to disconnect.
Flood-prone areas
The City runs a flood control program in areas such as West Thornhill, with major sewer and storm upgrades.
Heritage homes
Unionville and Markham Village have century-old homes with stone or block foundations.
Spring thaw
March and April snowmelt soaks the ground for weeks — the most common time for wall seepage and joint leaks.
Real Leaquida job siteMarkham’s Rebate Has a Deadline
- Building permits for rebate work must be obtained by April 30, 2027.
- Rebate applications are due by July 31, 2027.
- The property must be in a known flood-prone area or show flood risk.
- City approval comes before installation, and downspouts must be disconnected.
If you plan to use the rebate, start early: the City’s approval and permit steps take time, and the work has to follow them.
Source: City of Markham — Basement Flooding and Sewer Back-up Prevention (via TRREB program summary).
What Your Basement Is Telling You
Match what you see to the likely cause. We confirm it on site before recommending anything.
| What you see | Likely cause | Usual fix | Typical price |
|---|---|---|---|
| Water along the bottom of a wall after rain | Floor–wall joint leak, clogged weeping tile | Interior drainage + sump pump, or new exterior weeping tile | $50–$250 / lin. ft |
| A wet line coming down from a crack | Leaking foundation crack | Polyurethane or epoxy injection from inside | $500–$1,500 / crack |
| Water or sewage from the floor drain | Sewer backup during a storm | Backwater valve with alarm | $2,000–$4,200 |
| Water under a basement window | Window well with no drain or a blocked drain | Window well drain, gravel and liner | From $200 |
| Damp walls, white powder, musty smell | Slow seepage through the wall | Exterior membrane, or interior system for tight lots | $50–$250 / lin. ft |
| Sump pump running non-stop or failing | Undersized or worn pump, high groundwater | New pump, sealed lid, check valve, battery backup | $500–$3,900 |
Basement Waterproofing Across Markham Neighbourhoods
Markham combines heritage villages, 1950s–80s suburbs and large newer communities, so basements differ by area.
| Area | Typical homes | What we often check first |
|---|---|---|
| Unionville, Markham Village | Heritage and older homes | Stone or block walls, old drainage — exterior membrane, parging |
| Thornhill (Markham side), Bayview Glen | 1950s–70s homes | Weeping tile to sanitary, backwater valves — West Thornhill flood control area |
| Milliken, Middlefield, Armadale | 1970s–80s houses and townhouses | Failed weeping tile, cracks, floor drains |
| Raymerville, Markville, Unionville south | 1980s–90s homes | Cracks, window wells, sump pumps |
| Berczy, Wismer, Greensborough | 2000s homes | Sump pump reliability, battery backup, window wells |
| Cornell, Box Grove, Cathedraltown | 2000s–2010s homes | Settlement cracks, below-grade entries, builder warranty questions |
General guidance based on typical housing in each area — every home is different, so we confirm the cause on site.
Our Basement Waterproofing Services in Markham
From $100 / lin. ftExterior Basement Waterproofing
Excavation to the footing, membrane, drainage board and new weeping tile — water never reaches the wall.
Learn more →
From $50 / lin. ftInterior Basement Waterproofing
Drainage under the floor along the walls and a sealed sump pump — no digging in your yard.
Learn more →
$500 – $1,500 / crackFoundation Crack Repair
Injection that seals leaking foundation cracks from the inside, usually in one visit.
Learn more →
From $500 / unitSump Pump Installation
Sealed basin, reliable pump, discharge line and optional battery backup.
Learn more →
From $50 / lin. ftWeeping Tile & French Drains
New perforated weeping tile in clear stone to replace clogged or broken tile.
Learn more →
From $200Window Well Installation
Window wells with a proper drain so basement windows stop leaking.
Learn more →How Much Does Basement Waterproofing Cost in Markham?
Typical 2026 price ranges for Markham homes, before any rebate. Your exact price is written in your quote after a free inspection.
| Service | Price range | Typical duration* |
|---|---|---|
| Interior waterproofing | $50 – $120 per linear foot | 2 – 5 days |
| Exterior waterproofing | $100 – $250 per linear foot | 3 – 7 days |
| Full basement project | $3,000 – $35,000 | Depends on scope |
| Foundation crack repair | $500 – $1,500 per crack | Usually one visit |
| Sump pump installation | $500 – $3,900 per unit | Usually 1 day |
| Backwater valve | $2,000 – $4,200 per unit | Usually 1 day + permit |
| Inspection & written quote | Free | One visit |
*Typical for an average home; your schedule is confirmed in the quote. Costs rise with finished basements, deep foundations, decks, driveways and mature trees next to the wall.
Example: one 40-ft wall
- Interior drainage: about $2,000 – $4,800
- Exterior waterproofing: about $4,000 – $10,000
- Plus a sump pump if there is no pit yet
Simple arithmetic from the ranges above — not a quote.
Example: Markham rebates
- Weeping tile disconnection + sump pump: up to $5,000
- Indoor backwater valve: up to $1,750
- Outdoor backwater valve: up to $2,000
Fixed maximums from the City program — your eligibility is confirmed by the City.
Markham Private Plumbing Protection Rebate
The City of Markham pays fixed maximum amounts for work that keeps stormwater out of the sanitary sewer and stops sewer backup.
| Measure | Maximum rebate |
|---|---|
| Backwater valve — indoor (sanitary or storm lateral) | Up to $1,750 |
| Backwater valve — outdoor (sanitary or storm lateral) | Up to $2,000 |
| Weeping tile disconnected from sanitary, redirected to storm by gravity | Up to $3,000 |
| Weeping tile disconnected from sanitary, with sump pump | Up to $5,000 |
| Storm lateral reline or repair | Up to $2,500 |
| Sanitary lateral reline or repair | Up to $2,500 |
Rules that catch people out
- City approval and a building permit before installation, then inspections.
- Building permit by April 30, 2027; rebate application by July 31, 2027.
- The property must be in a flood-prone area or show flood risk.
- Downspouts must be disconnected from the City sewer.
- No outstanding fines, work orders, taxes or fees on the property.
What we prepare for your application
- Quote and sketch for the City’s technical review
- Building permit application and inspections
- Itemized, paid invoice per measure
- Downspout check before the job
- Clear advice on which measures your home qualifies for
Program details summarized from the City of Markham program as published by TRREB; rules and deadlines can change. Check the current details: markham.ca.
Permits and Inspections in Markham
Backwater valve
Needs City of Markham approval and a building permit before installation, plus inspections — all required for the rebate.
Weeping tile disconnection
Disconnecting weeping tile from the sanitary sewer and adding a sump pump is permitted plumbing work, reviewed by the City first.
Digging next to the house
Before any exterior excavation we request free utility locates through Ontario One Call, so gas, hydro and cable lines are marked.
Crack repair and interior work
Crack injection, interior drainage and sump pump replacement usually do not need a permit, unless the plumbing connection changes.
Our Process for Markham Homes
Free inspection
We check inside and outside, the sump pit, floor drains, grading and downspouts, and find the real cause.
Written quote
Scope, price, schedule and warranty in writing — plus which rebates you can claim.
Rebate & permits
We prepare the quote and sketch for the City review and arrange the building permit before the work.
The work
Our own crew protects your property and completes the job.
Test & paperwork
We test the system, clean up and give you the itemized invoice for any claim.
What Goes Into a Leaquida Waterproofing Job
Exterior and drainage
- Excavation to the footing and a cleaned, repaired wall
- Waterproof membrane plus a dimpled drainage board
- New 4-inch perforated weeping tile in clear stone
- Backfill, grading away from the house and site clean-up
Inside the basement
- Sealed sump basin, check valve and high-water alarm
- Battery backup pump on request
- Backwater valve with an access cover for cleaning
- Crack injection with polyurethane or structural epoxy
Real Leaquida job siteLocal Facts That Matter for Your Basement
- Unionville’s Main Street and Markham Village are among the best-preserved 19th-century main streets in the GTA.
- The Rouge River flows from Markham into Rouge National Urban Park.
- Water supply and trunk sewers are run by York Region; local sewers, permits and the rebate come from the City.
- Postal codes we serve: L3P, L3R, L3S, L3T, L6B, L6C, L6E, L6G.
Buying an older home in Markham? Ask about past floods, whether the weeping tile goes to the sanitary sewer and whether the City rebate was already used — and book an inspection before you close.
Real Leaquida Waterproofing Work
Photos from our own projects across Toronto and the GTA.
Markham Neighbourhoods We Serve
Also serving nearby
Basement Waterproofing in Markham: Questions & Answers
How much does basement waterproofing cost in Markham?
Interior waterproofing usually costs $50–$120 per linear foot and exterior waterproofing $100–$250 per linear foot. Most full projects in Markham fall between $3,000 and $35,000. The inspection and written quote are free.
What rebates can Markham homeowners get?
The Private Plumbing Protection Rebate pays up to $5,000 to disconnect weeping tile from the sanitary sewer with a sump pump, up to $3,000 if it drains by gravity, up to $1,750 for an indoor and $2,000 for an outdoor backwater valve, and up to $2,500 for lateral repair.
Is there a deadline for the Markham rebate?
Yes. The building permit for rebate work must be obtained by April 30, 2027 and the rebate application submitted by July 31, 2027. City approval is needed before installation.
Is interior or exterior waterproofing better for my Markham home?
Exterior waterproofing stops water before it reaches the wall and suits leaks through the walls where the outside is accessible. Interior drainage handles floor–wall joint leaks and high groundwater and avoids digging up landscaping. We recommend the right method after the inspection.
Can you waterproof a basement in winter?
Interior waterproofing, crack injection and sump pumps can be done year-round. Exterior excavation depends on ground conditions and frost, and we schedule it accordingly.
How long does a waterproofing job take in Markham?
Crack injection and sump pump installs usually take one visit, interior drainage 2–5 days and exterior waterproofing 3–7 days for an average home. Your schedule is written into the quote.
Does home insurance cover basement flooding?
It depends on your policy. Sewer backup and overland water are often separate coverages in Ontario, so check with your insurer. A backwater valve and sump pump can lower the risk of future claims.
Do you offer a warranty?
Yes. Every project comes with a written warranty on materials and workmanship. Terms depend on the service and are written into your contract.
Book a Free Basement Inspection in Markham
Tell us what is happening in your basement. We will find where water gets in, explain the City rebate and give you a written quote — no pressure, no obligation.
Call now — Mon–Fri 7 AM – 4 PM(416) 992-5858Office: 58 Six Point Rd, Etobicoke, ON M8Z 2X2
Email: info@leaquida.ca
Licence No.: P94 4418977 (licensed contractor)