Understanding Joint Trenching for Utilities

January 20, 2022 10:04 pm Published by Leave your thoughts

Whether water and power can share a trench is a matter of some debate. The bottom line is that codes aren’t clear on this topic. Some inspectors favor joint trenching while others don’t. Depending on the installation method used, it is possible to install both electrical and water lines, but these must meet minimum coverage depths due to safety protocols.

Read on to find out more about utility trenching services.


Water lines must run at a minimum depth of 6 inches with the option for 12 inches in areas that are liable to receive frost or other conditions leading to freezing during the winter months. Power can be installed at least 4 feet below grade, which often requires a trench 8 to 12 inches deeper than water pipes. The depth of the trench depends on factors like soil type and the location of the utilities in the trench.

With joint trenching, it’s typically best to allow for 12 inches between water and electric lines. For sewer and electric lines, 24 inches between is necessary.

How the process works

Joint trenching is favorable because it minimizes the excavation work necessary to move on with a project. Utilities are installed next to each other in a single cut of earth, which is later backfilled using sand, gravel and graded flat. With the subgrade compacted, as the joint base is laid first, then an impermeable geomembrane is used for water lines.

The joint base prevents punctures while power lines and other utilities are installed. The geomembrane can be placed over the combined ground; then more backfill is added to prevent gaps between utility lines prior to final excavation.

Utility companies need to coordinate an installation schedule before utility trenching services are completed. In many cases, electrical lines will go first.

Advantages and disadvantages of having water and electric lines in a single trench

The pros of this method include:

  • Lowers long-term costs: Water and electrical line costs over the long run will be reduced if a single trench is used. That’s because both utilities will have to travel less.
  • Less time: Contractors are only digging up a single path. This is faster than creating two separate paths and decreases the overall time spent on the project.
  • Minimizes space use: Sharing a trench allows for more land area to be used by the property owner.

However, there are drawbacks to having water and electric lines share a trench, including:

  • Possible code violations: National Electrical Code (NEC) standards require specific depths and soil conditions. When electricians don’t follow these codes during installation, the project could be deemed unsafe.
  • Initial costs: Installation can be more expensive than installing separately due to strict requirements. That said, your city or count may offer discounts on permitting fees which may offset this cost.

If you’re seeking the pros in joint trenching and directional drilling, check out everything Es7 Comm-2 U, Inc. has to offer. Our expertise in utility installation is unparalleled. Contact us right now to learn more and request a quote.

Categorised in: ,

This post was written by Writer

Leave a Reply

Your email address will not be published. Required fields are marked *