Oversized downspouts
Most builder gutters come with 2x3 inch downspouts. A 3x4 downspout has roughly twice the opening, carries much more water in a cloudburst, and lets pine needles pass instead of jamming in the elbow. We pair 3x4 downspouts with 6-inch gutters as a rule, and often with 5-inch gutters too.
We also look at how much roof drains to each downspout. A long run with one outlet at the far end overflows at the opposite corner in hard rain. Adding a second outlet, or splitting the run in the middle, usually fixes it.
Why it matters on clay
Much of the Midlands sits on red clay that takes up water slowly. Water dumped at a corner pools, soaks the soil right next to the footing, and finds its way into crawlspaces and basements. On sandier lots the problem looks different: the water carves channels, undermines walks and washes pine straw out of the beds. Either way, the fix is to move the water several feet from the house before it reaches the ground.
Washout at a foundation cornerExtensions, splash blocks and buried lines
- Extensions and splash blocks. The simplest step: carry the water a few feet out onto a splash block. Fine where the yard slopes away and nobody mows over them.
- Buried solid pipe. We connect the downspout to smooth-walled pipe in a trench and run it to a pop-up emitter in the lawn or to a daylight outlet at a lower spot in the yard. The pipe stays out of sight and out of the mower's way.
- Cleanouts. Where needles are heavy, we add a cleanout or a catch basin at the downspout so the line can be flushed.
Pop-up emitter in the lawnSC811 before we dig
South Carolina law requires notice to SC811 before excavation. The SC811 homeowner FAQ says to contact them at least three full working days, and no more than twelve, before digging. We file the ticket and wait for the marks. Private lines, such as irrigation, low-voltage lighting and septic laterals, are not marked by SC811, so we ask about them and hand-dig near anything uncertain.
Downspouts, by size
$6to$11
Per foot: 2x3 $6, 3x4 $8, 4x5 $11
Angi via The Gutter Report · Oct 2026 · national
Buried line, per downspout
$150to$350
With basin, pipe and emitter
HomeGuide via The Gutter Report · Oct 2026 · national
One underground extension
$800to$2,000
Angi drainage figure
Angi via The Gutter Report · Oct 2026 · national
Published prices for buried downspout lines vary widely, as The Gutter Report points out. Length, depth, roots and crossing a walk or driveway drive the difference. We price each line after walking the yard.
