If your sump pump runs every four minutes during a Glenview thunderstorm, your Northbrook window wells fill like bathtubs, or there’s a permanent soggy patch by the corner of the garage, the problem usually isn’t your foundation. It’s that roof and yard water has nowhere to go, so it goes down — against your foundation wall.
Exterior drainage is the cheapest water-management work you can do on a Chicagoland house, and it’s almost always the right first step before anyone talks to you about interior waterproofing.
Start With the Water You Can See
Do the math on your own roof. A 2,000 sq ft roof shedding one inch of rain produces about 1,250 gallons. If four downspouts dump that at the foundation, each one is delivering roughly 300 gallons within a few feet of your basement wall. No interior system fixes that; it just pumps it back out after it’s already inside.
Fix the cheap things first, in this order:
- Clean the gutters and confirm they’re pitched. Overflowing gutters are a drainage problem masquerading as a foundation problem.
- Extend downspouts 6–10 feet from the foundation — buried solid PVC to a pop-up emitter is the version that survives lawn mowing and looks like nothing.
- Regrade the first 10 feet. You want a 6-inch fall over 10 feet away from the house. Settled backfill against foundations is extremely common in homes 20+ years old, and topsoil is cheap.
- Fix window wells. Gravel-bottom wells that connect to drain tile, plus clear covers. A well with a clay bottom is a reservoir against a basement window.
- Only then consider a French drain or catch basin system.
French Drain vs. the Alternatives
“French drain” gets used for three different things. They solve different problems:
| System | Solves | Typical cost |
|---|---|---|
| Buried downspout extensions + pop-up emitters | Roof water at the foundation | $450 – $1,500 (per home) |
| Regrading / swale | Surface water flowing toward the house | $800 – $3,500 |
| French drain (perforated pipe in gravel, filter fabric) | Saturated soil, soggy yard, slow subsurface water | $35 – $75 per linear foot |
| Catch basin + solid pipe network | Standing water in a defined low spot | $1,800 – $6,000 |
| Dry well / infiltration chamber | Nowhere downhill to discharge (flat lots) | $2,200 – $5,500 |
| Curtain drain (upslope interceptor) | Water arriving from a neighbor’s higher lot | $45 – $90 per linear foot |
| Interior drain tile + sump | Hydrostatic pressure already at the footing | $4,000 – $12,000 |
Note the difference between the third and last rows. A French drain is preventive, moving water before it reaches the foundation. Interior drain tile is defensive, collecting water that already got there. Doing the defensive work while ignoring four downspouts at the wall means your sump pump becomes a permanent appliance running through every storm — and pumps that cycle constantly fail in three to five years instead of ten.
Glenview and Northbrook Specifics
Two local realities shape the design here.
Clay soil. Much of the North Shore sits on heavy clay with low permeability. Water doesn’t percolate; it perches in the more permeable backfill right against your foundation. That makes buried downspout extensions and grading unusually effective — and makes dry wells unusually disappointing unless they’re sized generously and placed in better soil.
Where you’re allowed to discharge. This is the part homeowners get wrong. In most Glenview and Northbrook neighborhoods you may not discharge onto a neighbor’s property, and connecting clear water (sump, downspout, footing drain) into the sanitary sewer is prohibited — it’s a real violation that villages enforce, and it contributes to basement backups across the whole block. Legal options are typically daylight discharge to grade on your own lot, a village-approved storm connection where one exists, or an on-lot infiltration system. Some regrading in flood-prone areas also triggers a permit. We confirm the discharge point with the village before we design the system, not after.
How to Diagnose Your Own Yard in One Rainstorm
Put on a jacket and go outside during the next real downpour. Fifteen minutes of watching beats any amount of guessing:
- Is any gutter overflowing? Where?
- Where does each downspout’s water actually travel? Follow it.
- Does water sheet toward the house anywhere along the perimeter?
- Are window wells filling?
- Do puddles remain more than 24 hours after the rain stops? Mark them.
- How often does the sump cycle — during the storm, and for how many hours after?
Photograph it. That set of photos tells us more than a dry-day inspection ever will, and it often points at a $700 fix rather than a $9,000 one.
Where Drainage Meets Your Plumbing System
Drainage work and plumbing overlap more than people expect. A yard that stays saturated raises the water table around the footing, which increases sump run time; heavy sump cycling with a single pump and no battery backup is how finished basements flood during power outages that accompany the same storm. And if you’re getting water in the basement without heavy rain, the cause may be a sewer or drain problem rather than groundwater — those two get confused constantly, and a camera inspection settles it in twenty minutes.
What a Properly Built French Drain Looks Like
The detail is what determines whether it lasts 30 years or 5:
- Trench: 12–18 inches wide, deep enough to establish continuous fall to the discharge point. Minimum 1% pitch — about 1 inch per 8 feet.
- Fabric: Non-woven geotextile lining the whole trench, wrapped over the top of the gravel like a burrito. This is the single most-skipped step, and its absence is why drains silt shut.
- Pipe: Rigid perforated PVC, holes down, not flexible corrugated. Corrugated pipe collects sediment in every ridge and crushes under vehicle or mower traffic.
- Stone: Washed 3/4-inch clean gravel — not crusher run, which contains fines that clog the fabric.
- Cleanouts: At the high end and at any bend, so the line can be jetted years later.
- Discharge: Daylight to grade on your own property with a rodent-proof grate, or a village-approved storm connection. Never a sanitary connection.
Ask any contractor bidding your job to describe those six items. The answer tells you everything about what you’re buying.
Maintenance: Twenty Minutes, Twice a Year
- Clean gutters in late spring and late fall. In Glenview and Northbrook’s mature tree canopy, that’s the minimum.
- Flush pop-up emitters and check they still open. Mulch and grass clippings block them.
- Clear catch basin grates and pull the sediment bucket if your basin has one.
- Pour five gallons into the sump pit to confirm the pump starts and the check valve holds.
- Test the battery backup and replace the battery every 3–5 years.
- Walk the perimeter looking for new settlement against the foundation, especially where utilities were trenched.
Do that and the expensive version of this problem generally never arrives. Skip it for five years and a $600 gutter-and-emitter maintenance issue turns into a wet finished basement and an insurance claim.
Frequently Asked Questions
Do French drains actually work in clay soil?
Yes, if designed for clay: adequate gravel envelope, non-woven filter fabric, real pitch (minimum 1% fall), and a legal discharge point. The failures we dig up are almost always no fabric, no pitch, or corrugated pipe crushed by traffic.
Can I connect my downspouts to my sump discharge line?
Don’t. Roof water volume will overwhelm the discharge line and can back-feed the sump pit. Keep them separate.
Should I do exterior drainage or interior drain tile first?
Exterior, almost always. It’s cheaper, less invasive, and frequently makes interior work unnecessary. If water is still entering after roof water and grading are corrected, then interior tile is justified.
How long does a French drain last?
A properly built one with filter fabric and clean gravel runs 25–40 years. One installed without fabric can silt up in 5–10.
Will regrading damage my landscaping?
Some disruption is unavoidable within the first 10 feet of the house. We plan around mature plantings where we can and tell you honestly what won’t survive before we start.
Is drainage work covered by insurance?
Generally no — it’s maintenance and improvement. But documented drainage improvements can help when you’re shopping for water-backup coverage endorsements.
Get Your Drainage Assessed
MMDS serves Glenview, Northbrook, Skokie, Evanston, Des Plaines, Mount Prospect, Arlington Heights, Wheeling, Palatine and Schaumburg. We’ll evaluate roof water, grading, window wells, sump performance and your legal discharge options — and recommend the least expensive fix that actually keeps the basement dry.
Call (847) 221-6280 or schedule an assessment. Sunbit and PowerPay financing is available on larger drainage projects.