It is 7:40 on a weekday evening and the saw next door is still running. Or it is Sunday morning and a crew has started breaking up a driveway. Or your new neighbor's air conditioner hums right under your bedroom window all night. You want to know one thing: is this actually allowed?
In unincorporated Los Angeles County, construction tools may not create a noise disturbance across a home's property line between 7:00 p.m. and 7:00 a.m. on weekdays, or at any time on Sundays and holidays § 12.08.440. Outside those hours, general noise reaching a home may not exceed 50 decibels by day and 45 at night for more than 30 minutes of any hour § 12.08.390.
One thing to settle first: these are county rules. They cover the unincorporated parts of Los Angeles County — places with no city government of their own. If you live inside a city, that city's own noise rules usually control. The Los Angeles County hub page is a good place to check which side of that line you are on.
Key numbers
| What | Limit | Source |
|---|---|---|
| Construction tools near homes (weekdays) | Not 7:00 p.m.–7:00 a.m. if it disturbs a neighbor | § 12.08.440 |
| Construction tools on Sundays and holidays | Not at any time, if it disturbs a neighbor | § 12.08.440 |
| Short-term construction equipment at a single-family home | 75 dBA 7 a.m.–8 p.m. (not Sundays/holidays); 60 dBA otherwise | § 12.08.440 |
| Long-term stationary construction equipment at a single-family home | 60 dBA by day; 50 dBA nights, Sundays and holidays | § 12.08.440 |
| General noise reaching a home (outdoors) | 50 dB 7 a.m.–10 p.m.; 45 dB 10 p.m.–7 a.m. | § 12.08.390 |
| Noise inside a neighboring apartment | 45 dB 7 a.m.–10 p.m.; 40 dB 10 p.m.–7 a.m. | § 12.08.400 |
| Air conditioner installed on or after Jan. 1, 1980, at the neighbor's property line | 55 dBA | § 12.08.530 |
| Garbage trucks compacting or collecting near homes | Not 10:00 p.m.–6:00 a.m. | § 12.08.520 |
A decibel (dB) is the unit sound is measured in. "dBA" means the reading is weighted to match how the human ear hears, which is how the county says every measurement must be taken § 12.08.370.
Construction noise: the hours and the loudness caps
The county ordinance handles construction two ways.
The hours rule. Running tools or equipment for construction, drilling, repair, alteration or demolition between 7:00 p.m. and 7:00 a.m. on weekdays — or at any time on Sundays or holidays — is prohibited when the sound creates a "noise disturbance" (the ordinance's term for noise that breaks one of its measured standards) across a residential or commercial property line § 12.08.440. There are two exceptions written into the rule: emergency work by public utilities, and work allowed by a variance (a written exception) from the county health officer.
The ordinance text in this section does not separately address Saturdays, so do not assume Saturday work is either banned or unlimited — ask the county.
The loudness caps. Even during allowed hours, the contractor has to keep noise at your home below set levels. The caps depend on whether the equipment is short-term and mobile (less than 10 days, like an excavator) or long-term and stationary (10 days or more, like a generator), and on the type of home § 12.08.440. For a single-family house, short-term mobile equipment is capped at 75 dBA on regular days from 7 a.m. to 8 p.m., and 60 dBA at night and all day Sundays and holidays. Apartments get slightly higher caps: 80 and 64 dBA.
The same section also requires gas- and diesel-powered construction equipment to have working exhaust and air-intake silencers.
Everyday noise: the neighbor's music, equipment, and more
For noise that is not construction, the ordinance sorts properties into four "noise zones": noise-sensitive areas, residential, commercial and industrial § 12.08.380. A home is in the residential zone, where the baseline is 50 dB from 7 a.m. to 10 p.m. and 45 dB from 10 p.m. to 7 a.m. § 12.08.390.
The baseline is not a hard ceiling for every second. It is the level noise may not exceed for more than 30 minutes in any hour. Shorter bursts are allowed to be louder — 5 dB louder for up to 15 minutes in an hour — and there is an absolute cap of the baseline plus 20 dB that may not be exceeded at all § 12.08.390. If the normal background noise in your area is already louder than the baseline, the background level becomes the standard instead.
Two details make the rules stricter for some sounds:
- Whines and bangs. A steady single-pitch whine (a "pure tone") or a sharp, sudden noise (an "impulsive" sound) is judged against limits 5 decibels lower § 12.08.410.
- Apartments. Noise from one unit into a neighboring unit is measured inside the neighbor's home, with limits of 45 dB by day and 40 dB at night § 12.08.400.
Air conditioners and pool equipment
Air conditioning and refrigeration equipment has its own table. For units installed on or after January 1, 1980, the limits are 55 dBA at the neighbor's property line and 50 dBA at the center of the neighbor's patio or outside their nearest living-area window § 12.08.530. Older units are allowed 5 dBA more at each spot.
If you are choosing where to put a new condenser, those measurement points are worth knowing: the county measures on the neighbor's side, not yours.
Why the county has these rules
The ordinance states its own goal plainly:
"It shall be the policy of the county to maintain quiet in those areas which exhibit low noise levels" — § 12.08.020
The same section declares noise that breaks the chapter's rules to be a public nuisance.
Homes near LAX: a building rule, not a noise rule
If you live near Los Angeles International Airport, a separate county zoning rule applies to your building work rather than to your neighbors. New homes, additions, alterations and repairs of residential buildings inside the airport's 65-decibel noise zone must meet extra sound-insulation building requirements § 22.76.010. Any deviation must be certified by an acoustical engineer to reach 45 decibels in every habitable room built or changed § 22.76.030.
What this post does not cover
The sections here do not address barking dogs, leaf blowers, car alarms, or the specific process for filing a complaint. Several rules in the ordinance also depend on decisions by the county health officer, such as variances and designated noise-sensitive zones around hospitals and similar facilities § 12.08.470. For those, contact the county directly.
Sources
- Los Angeles County noise control ordinance — title and policy, §§ 12.08.010–12.08.020
- Construction noise, § 12.08.440
- Decibel measurement, noise zones, exterior and interior standards, §§ 12.08.370–12.08.400
- Pure tone and impulsive noise correction, § 12.08.410
- Refuse trucks and air conditioning equipment, §§ 12.08.520–12.08.530
- Noise-sensitive zones, § 12.08.470
- LAX Noise Insulation Program — purpose, § 22.76.010
- LAX Noise Insulation Program — standards, § 22.76.030
