Dryer Vent Code Compliance Los Angeles

Three core requirements that affect most LA installations. (1) Vent diameter must be at least 4 inches throughout the run. Smaller diameter (3-inch reducers, mid-run constrictions) is non-compliant. (2) Maximum vent run length is 35 feet straight, with each 90-degree elbow counting as 5 feet of equivalent length. A run with three 90-degree elbows is limited to 20 feet straight (35 minus 15 for elbows). (3) Flexible plastic ducting is prohibited. Acceptable materials are rigid metal duct (galvanized or aluminum) or UL-listed semi-rigid metal flex for transitional sections behind the dryer only.

Yes if installed correctly. CA code allows attic routing with two conditions: the duct must be rigid metal (not flex), and the run must be sealed at every joint with metal foil tape (not duct tape, which fails under heat over time). Insulated duct is recommended through unconditioned attic space to prevent condensation. We see attic vent runs done correctly maybe 60% of the time in LA, the other 40% have flex duct that's degraded, joints that aren't sealed, or the run is unsupported and has sagged into traps that collect water and lint.

Yes. We provide dated invoices on every vent cleaning visit listing the work performed, before-and-after airflow measurements, technician's BHGS license number, and any code-compliance issues identified. LA condo HOAs in Marina del Rey, Westwood, Brentwood, and Beverly Hills increasingly require this documentation on an annual basis from residents. We work with HOA management directly when condos coordinate building-wide cleaning programs.

In LA condos and apartments built after 2000, multiple units often share vertical riser vent stacks that each apartment ties into. Cleaning these requires HOA coordination because the riser passes through multiple units' walls. Some buildings handle it as a building-wide annual program (best practice); others leave it to individual residents to coordinate during their own apartment cleaning. We've worked on common-vent programs in West LA high-rises and the pattern that works best is annual building-wide service rather than ad-hoc per-unit. Lint accumulation in the riser is a building-level fire risk.

The flexible duct connecting the back of the dryer to the wall stub is called the transition duct. CA code allows UL-listed semi-rigid metal flex for this transition only, typically 4 to 8 feet maximum length. Foil flex (the silver corrugated stuff) is non-compliant and fire-hazardous; replace with rigid metal or UL-listed semi-rigid. We see foil flex on year 10+ installations routinely and we replace it as part of any vent service when found.

Yes. Code compliance flags are part of every vent cleaning service we perform, we note any flex-duct violations, vent run length issues, missing or wrong-material exterior caps, kinked or crushed sections behind the dryer, unsealed joints, or other deviations. The notes are on the invoice. You can address them now (same-visit or scheduled return) or later, but we make sure you know about them. Particularly important on rentals and condos where the issues may have been inherited from a prior occupant.

Standard cleaning plus code review: $145 to $245 (no surcharge for the review, it's part of every cleaning). Foil flex hose replacement to code-compliant rigid: $85 to $125 added. Full vent run replacement (existing run is non-compliant or damaged): $385 to $725 depending on access requirements. Multi-unit HOA coordination service: quoted on-site based on building size. BHGS #A49573, EPA 608 Universal #1346255700410.