Interior drain tile for 120 ft of footing with 8 ft of lift
| Drain tile, installed$50–$100 per linear foot · about $8,400 typical | $6,000 – $12,000 |
|---|---|
| Pump sizedelivers about 33 gpm at 11 ft — the rating on the box is at zero head | 1/3 hp |
| Total dynamic head8 ft lift + 0.6 ft friction + 2 ft residual | 10.6ft |
| Design flow1 in/hr of rain over a 10 ft strip along 120 ft of footing | 12gpm |
| Pump starts per hour at design flowan 18-gallon working volume — over 30 starts an hour, and a larger pit buys more pump life than a larger pump | 42/hr |
| Drain tile length | 120ft |
Notes
- Where 12 gpm comes from. An inch of rain an hour, falling on a strip about ten feet wide along 120 ft of footing, is roughly 12 gallons a minute arriving at the tile. That is a design figure, not a measurement — the pit refill rate beats it: plug the pump, time how long the pit takes to fill a known depth, and size from that.
- Interior drain tile does not stop water getting in. It collects water that has already reached the footing and pumps it out. That is why it costs a fraction of excavating outside — and why it leaves the wall itself wet. If the problem is a damp wall rather than water on the floor, this is not the fix.
- The pump rating on the box is at zero head, which never happens. A pump advertised at 4,400 GPH delivers roughly half that against 11 ft of head. Ask for the pump curve and find 12 gpm at 11 ft on it. Every sump pump in every hardware store is marketed on the zero-head number.
- Cast iron over plastic, and a check valve that is serviceable. Cast iron housings dissipate heat and last markedly longer. The check valve stops the discharge column falling back into the pit — without one the pump moves the same water repeatedly and short cycles itself to death.
- A battery backup is not optional in a basement that floods. The storm that fills the pit is the storm that takes the power out; those are the same event. A backup pump on its own float, with a battery, is the difference between a wet floor and a finished basement.
- Where the discharge goes decides whether this works. At least ten feet from the foundation, sloped away, and never into the footing drain it just came from — which is a real and common installation error that recirculates water forever. In freezing climates the outlet needs a route that will not ice closed.
- Do the outside first if you can afford it. Downspouts extended well away from the wall, grade sloped away for the first ten feet, and gutters that actually work will fix a surprising share of wet basements for a few hundred dollars. Interior drain tile is what you install when that has been done and water still arrives.
$6,000 – $12,000, and a 1/3 hp pump
Interior drain tile runs along the inside of the footing, under the slab, and carries water to a sump. It does not stop water getting in — it collects water that has already arrived and pumps it out.
That is why it costs a fraction of excavating outside, and it is also why the wall itself stays damp. If the complaint is a damp wall rather than water on the floor, this is the wrong fix.
The pump rating on the box is a fiction
Every sump pump is marketed at its zero head flow — a condition that does not exist in any installation. Against the 10.6 ft of head here, the pump selected delivers what this page shows, not what the carton says.
Ask for the pump curve and find your flow at your head on it.
What decides pump life
Not horsepower — cycles. Every start wears the motor, and a small pit with a high inflow means starts every minute or two during a storm.
Where the cycle count is high, a larger pit buys more life than a larger pump. It is the cheaper of the two changes and almost nobody offers it.
Two things that are not optional
A check valve, so the discharge column does not fall back into the pit. Without one the pump moves the same water repeatedly and short cycles itself to death.
A battery backup. The storm that fills the pit is the storm that takes the power out — they are the same event. A second pump on its own float, with a battery, is the difference between a wet floor and a ruined basement.
Do the outside first if you can
Downspouts extended well clear of the wall, grade sloped away for the first ten feet, and gutters that work will fix a surprising share of wet basements for a few hundred dollars.
Interior drain tile is what you install when that has been done and water still arrives.
Nearby sizes
- Interior drain tile for 100 ft of footing with 8 ft of lift
- Interior drain tile for 150 ft of footing with 8 ft of lift
- Interior drain tile for 80 ft of footing with 8 ft of lift
- Interior drain tile for 180 ft of footing with 8 ft of lift
- Interior drain tile for 120 ft of footing with 6 ft of lift
- Interior drain tile for 120 ft of footing with 10 ft of lift
- Interior drain tile for 120 ft of footing with 12 ft of lift
Read more
- Epoxy or Polyurethane Crack Injection? — Structural vs WatertightOne restores strength, the other stops water. Choosing on price means choosing the wrong one about half the time.
- Exterior or Interior Basement Waterproofing? — What Each One Actually DoesOnly one of them keeps the wall dry. Whether that is worth two to three times the money depends on what you plan to do with the basement.
- Where Is the Basement Water Coming From? — Four Sources, Four FixesBuy the diagnosis before the solution. Waterproofing companies diagnose the problem they sell, and one of the four causes costs nothing to fix.