How to Spot and Replace Unsafe Asbestos Water Heater Vent Pipes in Older San Diego Homes

What Is a Transite or Asbestos Vent Pipe?

Older homes throughout San Diego County were often built with masonry chimneys or transite (cement-asbestos water heater vent) pipes for venting water heaters. These systems were common from the 1940s through the 1980s, but they’re no longer considered safe or effective by today’s building codes.

Transite pipes are made with asbestos, and while intact ones might seem harmless, age and wear can release harmful fibers. Most homeowners aren’t aware they have one — until it’s flagged during an inspection.

Why These Old Vents Should Be Replaced

1. Health Risks from Asbestos Exposure

When cracked, cut, or even disturbed, transite pipes can release asbestos dust into your home. This material is a known carcinogen and should only be handled by licensed professionals.

2. They Don’t Work with Modern Water Heaters

Today’s appliances are more efficient, but they vent at lower temperatures, which causes condensation in oversized, uninsulated chimneys or vent pipes. That moisture causes corrosion, poor draft, and sometimes allows carbon monoxide to backdraft into the home.

3. Moisture and Rust Can Damage the Unit

The trapped condensation doesn’t just stay in the pipe — it often drips back toward the water heater, leading to corrosion, rust at the flue collar, or even early equipment failure.

What’s the Solution? Upgrade to a Type B-Vent

The fix is straightforward: replace the old vent with a Type B-Vent, a double-wall metal flue that meets today’s plumbing and HVAC codes in California. B-Vent systems:

• Keep exhaust gases hotter for better draft

• Resist condensation

• Fit modern water heater flue collars

• Are easy to install by a licensed plumber or HVAC contractor

If asbestos-containing pipe is present, a licensed abatement contractor may be required to remove it — or it may be abandoned in place if sealed off and unused.

How to Know If You Have an Asbestos Water Heater Vent

• The vent looks like cement or gray pipe, often running into a chimney

• There’s no visible double-wall metal flue

• You see rust or water stains near the flue collar

• Your home was built before the 1990s and has never had the vent updated

💬 Quick Tip for Real Estate Agents

When showing older homes in San Diego, take a quick peek behind the water heater. If the vent looks like cement, clay, or runs into an old chimney, it’s likely outdated.

This is something buyers will be advised to correct — and it could delay closing if it’s flagged during escrow. Point it out early and be proactive!

 ✅ Call to Action: Book an Inspection or Consultation

At Turn Key Property Inspectors, we specialize in identifying outdated and unsafe systems — including water heater venting. We provide same-day digital reports, clear explanations, and actionable next steps so you and your client aren’t left guessing.

📞 Call (951) 553-8562 or schedule an inspection online today.