Trenchless sewer pipe repair in Denver

Three generations of pipe under one city

Denver grew in rings, and the sewer laterals under each ring belong to a different era. Capitol Hill, Baker, Washington Park, the Highlands and Park Hill were platted before 1950, and their service lines are short lengths of vitrified clay pushed together with mortar or tar at every joint. The mortar has long since turned to sand, and each open joint is a doorway for roots and a leak point for groundwater. The post-war tracts to the southeast and southwest were built fast, and many of them were plumbed with Orangeburg, a bituminous fiber pipe that softens with age, goes oval under the weight of the soil above it and blisters inward until the bore is half closed. Mid-century ranches across the city carry cast iron beneath the slab, where the invert rusts through from the inside and nobody sees it until the floor drain backs up. A repair plan that ignores which of these three pipes is in the ground is a guess.

What the soil and the trees add

Much of the Denver basin sits on bentonite-bearing clay. When it is wet it expands with real force; when it dries it pulls away and cracks. A buried pipe rides that movement, and after a few decades the joints have been worked open and the grade has been pushed out of true. Winter adds freeze-thaw heave near the surface, and the semi-arid climate means a sewer joint leaking a little warm water is the best-irrigated spot in the yard. Cottonwood, silver maple, elm and ash all send roots into it. Summer cloudbursts and hail-driven runoff then load the older combined sewers in central Denver, and a lateral with open joints takes on stormwater it was never meant to carry. The ground, in other words, does most of the breaking, and the pipe only has to be old enough to let it.

The repairs that keep the yard intact

Three methods cover nearly every lateral failure in Denver, and all of them work from a cleanout or a single small pit rather than a trench. Cured-in-place lining threads a resin-saturated sleeve through the existing pipe and hardens it in place, producing a jointless pipe inside the old one. Pipe bursting pulls a splitting head through a pipe that has collapsed or gone too oval to line, shattering it outward while towing in new high-density polyethylene behind. Sectional point repair installs a short cured liner over a single bad joint or crack when the rest of the line is sound. Before any of them, a hydro jetter scours roots and scale off the wall, and a camera records the pipe end to end so the method is chosen from evidence. The details of each are set out on the service pages, and the independent background on cured-in-place work is at the CIPP reference.

Permits, ownership and the alley

In Denver the service line is private property from the house to its connection at the main, even where that connection sits under the pavement. The city's Department of Transportation and Infrastructure runs the collection system and issues the Sewer Use and Drainage Permit that lateral work requires; touching the alley or the street adds a right-of-way permit on top. Older Denver blocks are gridded with alleys, and a large share of mains and laterals run beneath them, which puts the repair in a narrow corridor shared with garages, power poles and trash service. A trenchless crew needs a cleanout and a parking spot, not a trench the width of the alley, which is the practical difference between a one-day job and a week of closures. Addresses in the parts of Denver County served by other districts follow those districts' rules, and the installer sorts out which applies.

Houses, storefronts and plants

The same methods scale. A bungalow in Park Hill has eighty feet of clay to deal with; a LoDo warehouse turned into lofts has a hundred-year-old main drain under a slab that no owner wants cut; a restaurant on Colfax has grease-choked lines that need jetting before anything else; a food-processing plant toward Commerce City has process drains and a storm culvert that cannot be shut down for a month of excavation. The residential, commercial and industrial pages describe what changes at each scale, and what stays the same, which is that the pipe gets rebuilt from inside.

Who does the work

Installers listed on this site are verified for cured-in-place work, meaning their materials, training and inspection practice have been checked rather than taken on faith. the verified installer covering Denver is the verified installer for the Denver area, and the standard it was measured against is published at the verified installer directory. The first step is always a camera inspection, and the estimate that follows it is free.