If you've been called to a job in Tennessee, chances are you'll be working on water lines. And if you're going to be digging near them, it's important for you to know how deep water lines need to be buried. This varies from county-to-county and even from neighborhood-to-neighborhood if you're digging in a city.
To protect water lines, water line markers are often installed in roads near water lines to indicate where they are located.
Many water systems in Tennessee are private water systems (PWSs) which distribute water to 25 or more connections. They include both community water systems (CWSs), like those found in typical neighborhoods that serve the homes connected to water mains, and non-community water systems, like wells that supply one or two homes or businesses with their own water supply.
Tennessee has adopted the latest model building codes for water service piping requirements, including requirements for how deep water service lines need to be buried. The most recent updates were made effective January 1, 2014. The water service piping requirements in the 2013 and 2012 versions of the model plumbing code WTC were almost identical. The water supply and water distribution piping requirements in the 2012 version of the model building code CBC were also very similar to those in WTC.
Water Service Line Replacement
Water service line replacement can be tricky because water systems use different types of water service lines, which vary according to diameter and material. There are three main materials used for water service lines: galvanized steel, copper, and plastic (PVC).
According to section 27-505(1)(b) of Tennessee Plumbing Code [Title 1000 Chapter 5 Water Supply and Distribution System], water-service pipes must either:
- be buried not less than 30 inches below grade; or
- be buried not less than three inches below grade and located where water does not contact the water service pipe except through a watertight sleeve or coupling, or by means of underground watertight conduit.
If your water line is 30 -inches deep...
According to section 27-505(2), if your water-service pipes are 30 -inches deep, they need to be encased in concrete that completely encloses the water service piping. The concrete must be poured around the entire circumference of the water service piping (see Section 27-701 for details).
However, water lines can also be installed within precast concrete manholes provided certain requirements are met. For example, these manholes must be filled with an approved water-proofing material and watertight joints must be provided.
If your water line is installed within a concrete encasement or within precast concrete manholes, water service lines must meet the following requirements:
(a) Water service pipes shall not be attached to structural surfaces such as wood joists and walls; and
(b) water service pipes shall maintain the minimum cover required by this chapter.
Watch out for some common problems that can lead to water main breaks. Even water lines that are just 3 inches below grade can cause big problems if they're not protected.
If you require expert help, The Plumbing Co. is a team of expert water line replacement plumbers serving Tennessee.