What the roof stack does
Every drain in a house connects to a vent that runs up and out through the roof. Without it, water leaving a fixture creates suction and pulls water out of the trap, which lets gas into the room. The vent also lets air push in behind a draining toilet so it flushes cleanly.
The visible pipe is usually 2 to 4 inches across and sticks up through a rubber boot. Many homes have two or three. They all do the same job, so a blocked one affects the fixtures tied to it.
Symptoms and likely causes
| What you notice | Likely vent-related cause | What to do first |
|---|---|---|
| Gurgling after draining a tub or washer | Partial blockage or undersized vent run | Check for outdoor debris, then call a plumber if it persists |
| Sewer smell in one bathroom | Dry trap or a vent terminal too close to a window | Run water in the trap for a minute, then retest |
| Slow draining across several fixtures | Often the main line, sometimes a blocked vent | Test with a garden hose if safe, or have a plumber camera the line |
| Toilet bubbles when another fixture drains | Vent restriction on that branch | Do not keep flushing, call a plumber |
| Wet or stained ceiling near the stack | Failed roof boot or flashing | Set a bucket under the drip and call a roofer |
Sewer gas smell versus a gas leak
A sewer smell and a natural gas leak can both smell like rotten eggs. Gas utilities add a chemical called mercaptan to natural gas so people notice leaks. Enbridge Gas, which serves Herriman, says to leave the building immediately, avoid switches and phones indoors, and call 911 and the Enbridge emergency line at 1-800-767-1689 from outside.
Treat any strong rotten egg smell as gas first. Once you are sure it is not gas, then look for a dry trap, a failing wax ring, or a blocked vent.
Herriman winters and the vent pipe
The Utah Geological Survey describes the area around north Herriman as having cold, damp winters. In that climate, warm moist air rising from a drain can freeze on the cold lip of a small vent opening and close it down with frost. A vent pipe that is 1 1/2 inch can narrow in a hard freeze.
Herriman's own winterization notice tells residents to insulate exposed pipes in garages, crawl spaces, and other unheated areas. That advice applies to attic vent runs too. Insulating the section of vent pipe in the attic reduces frost buildup on its inner wall.
The city adopts the 2024 International Plumbing Code under Utah state law. Specific vent terminal diameters and clearances for Herriman are not something this guide can confirm, so ask the Building Department before you change the roof termination.
Gurgling drains or a sewer smell? Call (385) 488-1892 and a licensed plumber can trace the cause.
Call (385) 488-1892Snow, frost, and a quick ground check
After a heavy snow, glance at the stack from the yard. A cap of snow or a thick frost ring across the top is a warning sign. Never climb a snowy roof, because slips cause serious injuries every winter.
If you hear gurgling or see slow drains in freezing weather, run hot water in a bathroom sink for a few minutes. The warm air rising in the vent can melt light frost. If the problem returns, the pipe likely needs a larger terminal or attic insulation from a plumber.
Birds, squirrels, and other critters
Open pipes look like inviting nest sites. Sparrows and starlings pack vents with sticks and grass, and squirrels stash nuts down them. Wasps build small combs inside the pipe mouth.
A fine mesh cap sounds helpful but clogs with debris and frost. Plumbers use a coarse wire cage or a vent guard that leaves a wide opening. Ask before installing any cap, and leave wasps and nests to a professional, since a wasp sting on a ladder is a real danger.
Safe checks before you call
These stay on the ground or at a sink.
Walk the yard
Look up at each stack. Note debris, a leaning pipe, a cracked boot, or frost at the opening.
Run each trap
Pour a quart of water into rarely used drains and floor drains. A dried trap is the most common smell source.
Test for gurgle
Fill a tub partway, drain it, and listen at the tub and nearby sink. Repeat with the washing machine.
Photograph the roof
Use binoculars or a phone zoom to document what you see for the plumber.
A garden hose run down the vent from the roof is a plumber's test, and it needs a safe ladder setup. Do not attempt it in wet or icy conditions.
Clearance, honestly
Building codes limit how close a vent terminal may sit to windows and air intakes, and set a minimum height above the roof. Those numbers vary with the code edition and local amendments. Guessing them for your lot would not help you.
If your stack ends close to an openable window or an attic vent, mention it when you call. Dispatch from Herriman also covers Riverton and West Jordan, and the same question applies at any address.
Plumbing vent questions
Does Herriman's cold winter affect vent pipes?
Yes. The Utah Geological Survey notes cold, damp winters near north Herriman, and the city advises insulating pipes in unheated spaces. Frost can narrow a small vent opening, so insulate attic runs and check for gurgling after hard freezes.
Can I pour water down the vent to clear it?
A hose test is a plumber's check. It needs a ladder or roof access, and it can flood the system if the vent is blocked deeper down.
Is a gurgling drain always a vent problem?
No. Gurgling can also come from a partial clog in the drain or the main line. A plumber can tell the difference with a camera or a cable test.
Do all homes have a vent on the roof?
Most do. Some fixtures use air admittance valves under the sink, which open to let air in without a roof pipe. These are code limited, so ask the building department.
What if the smell is only in the garage floor drain?
Dry floor drain traps are common. Pour a quart of water down it and add a little mineral oil on top to slow evaporation.
Need someone to look at the roof stack? Call (385) 488-1892 to book a visit.
Call (385) 488-1892Sources and standards
Local rules and figures in this guide come from the public sources below. Fees and codes change, so confirm the current version before you act on it.