Interior or Exterior Basement Waterproofing: Choosing in Des Moines

Interior drain tile manages water once it reaches the wall: a drain under the floor edge carries it to a sump pump. Fixr lists $40 to $120 per linear foot (February 2026). No digging outside; the floor and any finishes along the wall are disturbed instead. More on interior drains.

Exterior waterproofing keeps water off the wall: excavation to the footing, a membrane, a new footing drain and better backfill. This Old House lists $7,000 to $15,000, and $20,000 or more for full excavation (March 2026). More on exterior work.

Older city homes. Many older Des Moines houses sit close together on narrow lots with porches and driveways along the walls, which makes excavation hard. Interior systems are often the practical choice there.

When outside work is worth it. A wall that also needs outside repair, a finished basement you do not want to tear out, or water entering high on the wall can make exterior work the better value.

Either way, check the outside first. Gutters, downspouts and grading are cheap and can shrink the problem a great deal. See yard drainage, then compare written quotes for each method.