Main Water Line Repair in Longmont, CO
The pipe between the street and your house is the one you never think about until the yard is soggy or the pressure drops. We find the problem and fix it with as little digging as possible.
Water Line Repair in Longmont: Fixing the Pipe That Feeds Everything
Your main water service line carries every drop of water your home uses, from the city shutoff near the street to the point where the pipe comes through your foundation. In most cases that stretch of pipe is the homeowner’s responsibility, not the city’s, and it spends its whole life buried in Front Range clay that swells when wet, shrinks when dry and freezes hard every winter. Sooner or later, something gives.
M&M Heating, Cooling, Plumbing & Electrical has repaired and replaced water lines around Longmont since 1996. We work on every material you are likely to find underground here: older galvanized steel that has rusted from the inside out, polybutylene that was common in homes built from the late 1970s through the mid 1990s, copper that has pitted in our mineral-heavy soil, and newer PEX or poly lines that were damaged by settling or careless digging.
Our plumbers start by confirming the leak is actually in the service line and pinpointing where, using acoustic and electronic locating equipment so we dig in one spot instead of trenching the whole yard. If the line is worth saving, we repair the failed section. If it is near the end of its life, we will tell you honestly and walk you through replacement, including whether a less invasive trenchless approach is a fit for your yard.
Either way, you get an upfront price before any shovel hits the ground.
Signs Your Main Water Line Needs Attention
A service line leak rarely announces itself inside the house. These are the clues homeowners usually notice first.
Wet or Sunken Spots in the Yard
A patch of lawn that stays soggy when the rest is dry, an unusually green strip running toward the street, or ground that has settled along the pipe path usually means water is escaping underground.
Low Pressure at Every Fixture
If pressure drops in the whole house at once, not just one faucet, the problem is often upstream of your plumbing: a leak, a partially collapsed line or an old galvanized pipe choked with corrosion.
A Water Bill That Jumped
A sudden spike with no change in habits is a classic service line symptom. The meter keeps spinning even when every tap is off, and the water is soaking into the ground where you cannot see it.
Water Seeping at the Foundation
Dampness on the basement wall or floor where the service line enters, or water pooling against the foundation outside, can point to a leak right at the entry point or just outside it.
Rusty or Discolored Water
Brown or yellow water from cold taps, especially first thing in the morning, often means an old galvanized service line is shedding rust. It is a sign the pipe is nearing the end of its life.
Hissing or Running Sounds
A faint hiss or the sound of running water near the meter or where the line enters the house, with every fixture off, usually means pressurized water is escaping somewhere along the line.
Spot Repair vs. Full Line Replacement
We recommend the option that makes sense for the age and condition of your line, not the one with the bigger ticket.
Spot Repair
Best when the line is a sound material with a single point of damage, such as a crushed section, a failed fitting or a nick from digging.
- One excavation at the leak location
- Lower upfront cost
- Good fit for copper, PEX and poly lines in otherwise good shape
- Fastest way to restore water service
Full Line Replacement
Best when the line is galvanized, polybutylene, or has already leaked more than once. Patching a failing pipe just moves the next leak down the line.
- New line from the curb stop to the house
- Trenchless pull-through available on many properties
- Restores full pressure and flow
- Eliminates repeat repair calls
The M&M Difference
Underground work is where a contractor's honesty matters most, because you cannot see what they are doing.
We Locate Before We Dig
Electronic and acoustic leak locating lets us pinpoint the failure and open one hole instead of a trench across your yard. Less mess, less restoration, lower cost.
Trenchless When It Fits
Where the route and soil allow, we can pull a new line through the path of the old one with only small access pits at each end. Your lawn, driveway and landscaping stay intact.
Upfront Pricing, No Surprises
You get a firm price before we start, with the repair and replacement options laid out side by side. Nights and weekends cost the same as a Tuesday morning.
Family-Owned Since 1996
Nearly 30 years of digging in Longmont soil means we know what is buried here and how it fails. Every job is backed by our 100% satisfaction guarantee.
Our 4-Step Process
From the first phone call to a freshly backfilled yard, here is what to expect.
Confirm & Locate
We verify the leak is in the service line, check pressure and meter movement, and use locating equipment to mark the exact spot so we dig once.
Options & Upfront Price
We explain what we found, whether a spot repair makes sense or the line should be replaced, and quote each option before any work starts.
Repair or Replace
We call for utility locates, excavate carefully, then repair the section or install a new line below the frost line, and we will tell you if a trenchless approach is an option.
Test, Backfill & Restore
The line is pressure-tested and flushed, the excavation is backfilled and compacted, and we leave the site as close to how we found it as we can.
Water Line Repair Questions
Who is responsible for the water line, me or the City of Longmont?
In most communities, including Longmont, the utility owns the main in the street and the meter, while the homeowner is responsible for the service line from the shutoff at the property line to the house. That means a leak in your yard is usually yours to fix. We can confirm where the responsibility splits on your property before any work begins.
How do you find a water line leak without digging up the whole yard?
We start with a pressure test and a look at the meter to confirm water is escaping. Then we use acoustic listening equipment and electronic line locators to trace the pipe and pinpoint the leak. On most properties that lets us open a single hole over the problem rather than trenching from the street to the house.
What is trenchless water line replacement?
Instead of digging a trench along the entire pipe route, we open a small pit at each end and pull a new line through the path of the old one. It protects lawns, driveways, mature trees and landscaping, and the job usually goes faster. Not every property qualifies, since the route, soil and existing pipe all have to cooperate, so we evaluate it on site.
Should I replace my galvanized or polybutylene water line even if it is not leaking?
If the line is galvanized steel, it is corroding from the inside and restricting flow, and a leak is a matter of when, not if. Polybutylene has a well-documented history of sudden failure. If you are already planning yard work, a driveway, or a remodel, replacing the line proactively is often less disruptive and less expensive than an emergency dig later.
How long will my water be off during the repair?
For a spot repair, water is typically off for a few hours while we expose the pipe and make the fix. A full replacement often takes most of a day, and we keep the old line in service as long as possible before switching over. We will give you a realistic timeline with your quote so you can plan ahead.
Does expansive clay soil really damage water lines?
Yes. Much of the Front Range sits on clay that expands when it absorbs moisture and contracts as it dries. That constant movement stresses buried pipe, especially at fittings and where the line enters the foundation. Add freeze-thaw cycles and older brittle materials, and you have the main reasons service lines fail around Longmont.
Think Your Water Line Is Leaking?
Open 24/7 | Emergency Service Available
Call (720) 608-3973Water Line Repair Across the Front Range
Proudly serving Longmont, CO and surrounding communities including Erie, Frederick, Firestone, Dacono, Mead and Berthoud.
Primary Service Area
- Longmont, CO
- Erie, CO
- Frederick, CO
- Firestone, CO
- Dacono, CO
Extended Area
- Mead, CO
- Johnstown, CO
- Berthoud, CO
- Niwot, CO
- Gunbarrel, CO
Also Serving
- Lafayette, CO
- Louisville, CO
- Superior, CO
