How to Inspect Your Water Heater Venting — Anderson Island, Washington
Complete checklist with climate-adjusted recommendations for Anderson Island, Washington
Overview
Gas and propane water heaters produce combustion gases including carbon monoxide that must be safely vented outside your home. A disconnected, corroded, or improperly sloped vent pipe can allow deadly carbon monoxide to accumulate indoors. Annual inspection of the vent system is a critical safety check.
Step-by-Step Guide
Identify your venting type
Determine whether your water heater uses atmospheric venting (metal vent pipe rising from the top through the roof), power venting (PVC pipe exiting through a wall with a motorized fan), or direct venting (sealed pipe system with no indoor air intake). The inspection differs for each type.
Check the vent connector at the water heater
For atmospheric-vent units, verify the vent pipe is securely connected to the draft hood on top of the water heater. It should be fastened with at least three sheet metal screws per joint. Check for rust, gaps, or separations at the connection point.
Inspect the vent pipe along its entire run
Trace the vent pipe from the water heater to where it exits the building. Look for rust holes, disconnected sections, sagging, or damage. Each horizontal section must slope upward toward the chimney or exit point at a minimum of 1/4 inch per foot of run.
Verify proper slope and support
Use a level or observe visually that the vent pipe slopes continuously upward. There should be no dips, sags, or low points where condensation can collect. Horizontal runs should be supported with metal straps every 3-4 feet.
Test for backdrafting
With the water heater running, hold a lit match, lighter, or thin piece of tissue near the draft hood opening at the top of the water heater. The flame or tissue should be drawn toward the vent pipe, not pushed away. If combustion gases blow toward you, the vent is backdrafting, which is a dangerous condition requiring immediate attention.
Check the vent termination outside
For power-vent units, check that the PVC exhaust pipe outside is clear of obstructions, bird nests, ice, or insect nests. For atmospheric-vent units that share a chimney, check the chimney cap for blockages. The termination must be at least 12 inches above the roof line or as specified by code.
Inspect for signs of carbon monoxide risk
Look for soot marks or discoloration around the draft hood, vent connections, or on the top of the water heater. Soot indicates incomplete combustion or backdrafting. Check that your carbon monoxide detectors are working and positioned near the water heater and sleeping areas.
What You'll Need
Tools
- - Flashlight
- - Screwdriver (to check vent screws)
- - Level (to check slope)
- - Match, lighter, or tissue paper (for draft test)
- - Mirror (for viewing behind the unit)
Cost Estimates
DIY Cost
$0 (inspection only)
Professional Cost
$150 - $400 for vent pipe repair or replacement; $500 - $1,000 for chimney liner if needed
Safety Tips
- If you smell gas or suspect carbon monoxide, leave the house immediately and call 911. Do not use electrical switches or open flames.
- If the backdraft test shows gases blowing into the room, shut off the water heater and ventilate the space immediately. Do not use the water heater until the venting is repaired.
- Ensure your home has working carbon monoxide detectors on every level and near sleeping areas.
- Do not use foil tape or duct tape on vent pipes. Use only approved metal screws and connectors rated for flue gas temperatures.
When to Call a Professional
Call a licensed plumber or HVAC technician immediately if the vent pipe is disconnected, has rust holes, shows signs of backdrafting, or if you see soot deposits around the water heater. Also call a pro if the vent shares a chimney with a fireplace and you want to verify proper sizing and draft.
Pro Tip
If you are replacing an older atmospheric-vent water heater, consider upgrading to a power-vent or direct-vent model. They are more efficient and eliminate the risk of atmospheric backdrafting. Power-vent units can be vented through a wall with PVC pipe, which is cheaper than running metal vent pipe through the roof.
Common Mistakes to Avoid
- Using PVC pipe for atmospheric vent connections. PVC is only approved for power-vent and high-efficiency condensing units. Standard atmospheric vents require single-wall or double-wall metal vent pipe.
- Reducing the vent pipe diameter from what the manufacturer specifies. A smaller pipe restricts flow and causes backdrafting.
- Ignoring a vent pipe that is 'mostly connected' with a small gap. Even a small gap can leak enough carbon monoxide to be dangerous.
- Failing to check for backdrafting after changes to the home's air sealing (new windows, insulation, exhaust fans). Tighter homes are more prone to backdrafting because there is less makeup air for combustion.
Local Plumbers in Anderson Island
Shield Plumbing & Remodel
Tacoma, WA
(253) 523-2809
At Your Service Plumbing
Tacoma, WA
(253) 448-8136
Mikes Plumbing Tacoma
Tacoma, WA
(253) 740-3248Founding Member
Premium spot in Anderson Island
Ambassador
Lead the Anderson Island community
Founding Member
Premium spot in Anderson Island
Anderson Island Housing Market
Median Home Price
$465,000
Homes for Sale
8
Price per Sq Ft
$336
Local Pros
560
Home Service Professionals Near Anderson Island
Median Household Income
$72,074
Median Home Value
$477,600
Homeownership Rate
98.7%
Population
1,341
Median Year Built
1992
Source: U.S. Census Bureau, ACS 2023 5-Year Estimates
Fair Market Rents — Anderson Island
Studio
$1,428/mo
1 Bedroom
$1,605/mo
2 Bedroom
$1,971/mo
3 Bedroom
$2,733/mo
4 Bedroom
$3,102/mo
Source: HUD FY2026 Fair Market Rents — Tacoma, WA HUD Metro FMR Area
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