Find the failed run before you replace the whole yard.

O’Fallon Quality Drainage treats pipe repair as evidence-led excavation. See French drain repair, downspout drainage, and pop-up emitter installation.

Finding the failed run without guessing

Start at the inlet and the named outlet

Start at the inlet and the named outlet. A hose, a cleanout, or a camera tells you whether the blockage is 8 feet in or at the pop-up. Random pits waste restoration.

Build a simple map before digging: inlet, cleanout, visible turns, crossings, suspected route, and outlet. Test in the direction of flow when safe to do so and record what appears at the release. A missing response can mean a blockage, a disconnected line, a low outlet, or an incorrect assumed route, so it is evidence rather than a final diagnosis.

Crush, offset, root, and silt failure modes

Crush under a later driveway looks like a kink

Crush under a later driveway looks like a kink. Offset joints catch debris. Roots enter at gaps. Silt means pitch or a missing trap. Each mode has a different splice.

The repair record should distinguish what was observed from what is suspected. A camera image, exposed joint, standing water level, or measured elevation can support a particular repair. Surface ponding alone cannot tell whether the pipe is crushed, undersized, back-pitched, or simply discharging to a blocked outlet.

Open-cut versus limited excavation

Matching materials

Mixing thin corrugated with rigid pipe without proper couplings creates the next offset.

A short, accurately located defect can be a small pit. A collapsed corrugated run under a whole side yard is a replacement. Do not buy a lining product from a webpage that this site does not evaluate.

Choose the opening after the defect is located as closely as practical. The scope should state what surface will be opened, how utilities and adjacent features are protected, how the joint will be made, and how the area will be restored. A small pit is not automatically a small repair if the new connection cannot be reached or tested from it.

Matching pipe material and diameter

Downstream diameter should not shrink without a reason

Downstream diameter should not shrink without a reason. Upstream grit should not enter a smaller perforated sock. Write diameter, material, and coupling type.

Ask whether the repaired segment carries roof water, surface inlet flow, a French-drain collector, or only a solid discharge. Those flows have different debris and inspection needs. The replacement should preserve a clear, serviceable path to the outlet, with compatible couplings and a layout that does not create a new hard-to-reach sag.

Reinstating pitch to the same outlet

If the outlet was always too high, a perfect splice still holds water

If the outlet was always too high, a perfect splice still holds water. Measure outlet elevation before promising a repair. Sometimes the repair is a new release, which is closer to new French drain installation.

Record the upstream and downstream elevations used for the repair instead of describing the line as simply sloped. A repair can be mechanically sound and still hold water if a downstream rise, buried pop-up, or untested connection removes the needed fall. The outlet check belongs before final backfill, when correction is still possible.

Testing after reconnection

Run water

Run water. Watch the outlet. Restore. Then watch a storm. Keep the test photos. Missouri 811 applies to repair pits too.

The test should cover the repaired joint and the release, not just whether water disappears at the inlet. Photograph the exposed connection before covering it, then record water emerging where expected. The next-storm observation can reveal a separate surface or capacity issue that a short hose test could not reproduce.

When the outlet, not the pipe, is the defect

A perfect pipe to a buried pop-up in a hole will still pond

A perfect pipe to a buried pop-up in a hole will still pond. Fix the release. National install cost bands are not a repair menu; ask for a located-defect price.

If the outlet cannot be reached, cannot release on the lot, or is lower only on an old sketch, treat that as a design question rather than selling a splice. A repair quote should say whether it restores an existing valid outlet or requires a new release path. That distinction prevents a localized excavation from being marketed as a whole-system cure.

Close the repair file with a diagram of the tested route, the exposed defect, the replacement material, and the observed release. Note what was not inspected, such as a longer buried section or an inaccessible downstream connection. That record lets a later provider decide whether a new symptom is related to the repaired segment instead of repeating exploratory digging across the yard.

A repair should also state the decision point that ended investigation: camera evidence, a test pit, a failed hose test, or a confirmed outlet problem. Without that boundary, a property owner may read a limited repair as evidence that every buried line has been inspected. Clear limits make the work easier to evaluate after the next storm.

Keep the before-and-after photos with the invoice and route sketch. If water returns, the provider can compare the new observation to a known inlet, repaired segment, and outlet rather than starting with a broad assumption about the whole yard.

That record should identify the repair boundary and the next inspection point, so routine maintenance does not become another speculative excavation.

If a downstream route remains unverified, state that plainly. The next decision should follow observed flow, not an assumption that one repaired joint proves the condition of every buried segment.

Include any known as-built sketches with your contact request. A nearby St. Peters parcel still needs its own pipe inspection and outlet review.