How much wall is wet
A drain along one wall is a smaller job than a drain around the whole basement. The estimate follows the wall that takes water, not the size of the house.
Ask where the water shows up and whether the plan covers only that wall or the full perimeter.
How the water gets in
A single crack is one kind of job. Seepage along the floor joint is another. A window well that overflows is a third. The fix, and the price, follow the entry point.
A good estimate names the entry point and explains why the proposed work addresses it.
Access and finishing
A basement full of stored boxes or finished walls takes longer to work in. Carpet, paneling and drywall along the wall may need to come off before a drain can go in.
Ask whether the estimate includes putting back what is removed, or only the waterproofing itself.
The pump and where the water goes
A sump pump, a battery backup and a discharge line are separate pieces. A longer discharge run, or a pump sized for a heavy flow, changes the total.
The estimate should say where the water will end up. If it does not, ask.
Work outside the house
Regrading the yard, extending downspouts and clearing around the foundation are often the least expensive fixes and can reduce the water that reaches the wall in the first place.
Some jobs need both inside and outside work. A good estimate separates them so you can see each one.
