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The number a homeowner wants is a price per lineal foot of drain tile. That number is not a takeoff. An 80 lf finished basement with an existing sump is not the same job as a 55 lf seepage house with four window wells and a new pit. The footage is smaller on the seepage house. The hours are not.
Open the free bid calculatorInterior French drain is cut, haul, pipe, gravel, and pour-back. Exterior excavation is a different job — spoil, membrane, and a yard to put back. Crawl encapsulation prices floor vapor and wall liner, not drain footage. Gutter work prices eaves and downspouts. A retaining wall prices height and geogrid. Waterproofing prices water-entry points. Quoting all three from a published per-lineal-foot number is how the first window well eats the field margin.
Each window well is typically a cover, a drain into the interior system, and a few hours that never appear in the perimeter tape. A new pit is excavation and a liner, not a swap on an existing crock. Battery backup and freeze-proof discharge are adders that get forgotten on a brochure special. On the sample rates a 55 lf seepage house with four wells, a new pit, a battery backup, and 60 feet of freeze-protected discharge prices about $15,148 ($275 per lineal foot, 74 crew-hours). The same shop’s 80 lf finished basement with an existing 1/3 HP sump and 20 feet of discharge prices about $12,157 ($152 per lineal foot, 59 hours, walk-away $9,118). Matching the brochure job’s per-foot number on the seepage house is how that job becomes a loss.
Interior drain cuts a strip of slab. Exterior excavation opens the foundation, hauls spoil, and restores landscaping. On the sample rates a 100 lf exterior job prices about $26,206 ($262 per lineal foot, 207 crew-hours) — more than double the 80 lf interior brochure job, not because the wall is longer but because the dirt is. Treating that as a blended “add 30%” is how the yard-destroyer special that looked fine turns into a loss after the first dump ticket.
A $36/h tech loaded at 32% payroll burden is $47.52. Margin is a share of the price you send, not a markup on cost. The walk-away price is total cost — below that the job makes nothing before you take a dollar home. Replace every rate with your invoices before you send either number.
This is not an engineering specification, a dry-basement warranty, a hydrostatic-pressure guarantee, a permit, or a recommended market price. It is arithmetic on the numbers you type. Water-entry diagnosis, pump sizing, and whether the discharge can freeze are yours to confirm.
Charge from perimeter lineal feet, wall height, window wells, crack repair, new versus existing sump, backup pump, discharge run, loaded labor, overhead, and a margin that is a share of price. A default 80 lf finished basement with an existing 1/3 HP sump and 20 feet of discharge prices around $12,157 on the sample rates in this calculator — about $152 per lineal foot.
Homeowners measure the basement perimeter. Window wells, a new pit, battery backup, and freeze-proof discharge do not scale with that footage. Matching a cheaper per-foot quote written for a finished basement with an existing sump is how a seepage house becomes a two-day loss.
No. On the sample rates a 55 lf seepage house with four window wells, a new pit, a battery backup, and 60 feet of freeze-protected discharge prices around $15,148 ($275 per lineal foot), while a longer 80 lf finished basement with an existing sump prices around $12,157 ($152 per lineal foot).