Home › Services › Trenching for water, sewer, power and drain lines around Knoxville
A trench is a narrow excavation, longer than it is wide, dug to bury something: a water service from the meter, a sewer lateral to the main or a septic tank, electrical conduit out to a shop, a gas line, a downspout drain or a footing drain. Trenching looks simple, but it's the kind of excavation most likely to hit an existing line and most likely to hurt someone if the walls cave in.
Tennessee law requires notice to Tennessee 811 at least three full working days before digging. A ticket stays valid for 15 calendar days after its legal start date, according to Tennessee 811's FAQ, so a long job may need an update. Two points cause most of the trouble on trenching jobs:
The Tennessee 811 guide has the full timeline.
Under OSHA's rules, summarized in its trenching fact sheet, a trench 5 feet deep or more needs a protective system (sloping, benching, shoring or a trench box) unless it's cut entirely in stable rock. Spoil piles have to sit at least 2 feet from the edge, a competent person has to inspect the trench daily and after rain, and the air should be tested in trenches deeper than 4 feet. Sewer laterals and deep water lines easily get past 5 feet. If someone on your job will be climbing into the trench, ask how it will be protected.
A trench that runs across a ridge lot around Knoxville may go from clay to solid ledge in a few feet. A trencher or excavator bucket that handles dirt won't cut dolomite. Expect a hammer, a rock trencher or a reroute, and ask in advance how that extra time is priced. On steep runs, trenches can become channels for water, so the backfill should be compacted and the surface restored quickly, with check dams or other controls where the slope calls for them.
| Line | Who usually handles it |
|---|---|
| Water service or sewer lateral connecting to a public system | A plumber or utility contractor, often working with an excavator. The utility will have its own connection and inspection rules. |
| Electrical conduit to a shop, well or gate | An electrician sets the conduit and wire, and an excavator may dig and backfill the trench. |
| Drain lines, downspout extensions, footing drains | An excavation or drainage contractor |
| Long rural runs across acreage | An excavation contractor with a trencher or excavator, and a plan for any rock |
Pipe usually sits on bedding material, gets covered by hand-placed fill, and then the rest of the trench is backfilled in layers. If a trench is just pushed full and left, it sinks into a long rut after the first heavy rains. Ask whether the price covers compaction, topsoil and seed or straw, and whether any driveway or road crossings are included.
Usually not. Tennessee 811 says privately owned lines, like water services and sewer laterals on your side, may need to be located by the owner or the excavator. Private locating companies can do it.
OSHA requires a protective system at 5 feet or deeper unless the trench is entirely in stable rock. Shallower trenches still need a competent person to judge whether protection is needed.
You can start once every utility on the ticket has answered through Positive Response or the legal start time has passed. If something looks unmarked, Tennessee 811 says to submit a second notice.
This site doesn't own a single machine. We pass your request to an independent excavation contractor in the Knoxville area, and that contractor looks at the ground, quotes the work and does it.