Proposed changes to the county's noise ordinance are upsetting off-road enthusiasts who say the new rules could severely restrict where they can play in the backcountry.

Residents concerned about noise from off-road vehicles said the proposed rules are not strict enough.

As part of an update to some county regulations, officials with the Planning and Land Use Department are proposing stricter noise rules in the unincorporated county -- particularly with regard to off-road vehicles.

The current noise ordinance is outdated and needs to be changed, said Joe Farace, a county planning manager.

The proposed changes would clarify noise levels in residential, commercial and agricultural areas.They also would set limits on construction and off-road vehicle noise, as well as new standards for measuring those sounds.

"We're revamping it because it's so old and it hadn't been done," Farace said.

The changes were first aired at a Planning Commission hearing in May. The draft ordinance drew many comments, including people who thought it was not strict enough, and off-roaders who thought it was too restrictive.

It was the changes to the off-road vehicle noise limits that drew the most comments.

"I like to see people enjoying their property," said Michael Adams, a Vista off-roader and a concert sound engineer. "I'm not against this ordinance, but with these noise levels, you could bust your neighbor for mowing his lawn."

The ordinance proposed in May would have limited noise levels for off-road vehicles -- such as dirt bikes, go-carts and dune buggies -- to 65 decibels between the hours of 7 a.m. to 7 p.m. Sixty-five decibels is often described as the sound of a loud conversation between two people.

Based on complaints from the public and comments from several members of the planning commission, county officials modified the proposal to allow for louder sound. The maximum noise level for off-road vehicles during the day was increased from 65 decibels to 82, which is sometimes described as the sound of a loud yell.

State law requires that off-road vehicles built after 1986 limit their noise to 96 decibels. A typical lawn mower produces a sound of about 90 decibels.

At night, noise levels were increased from 55 decibels to 77 decibels for the hours between 7 p.m. and 10 p.m. Noise levels were left unchanged at 55 decibels between 10 p.m. and 7 a.m.

The revamped version of the proposed ordinance is scheduled to be heard at the Planning Commission's meeting on Oct. 31.

The commission makes recommendations on planning and land-use matters, such as the proposed ordinance. However, the Board of Supervisors ultimately will decide whether to adopt or reject the changes.

Similar changes have been controversial in communities throughout Southern California.

In 2006, Riverside County approved a noise ordinance that requires landowners in unincorporated areas to obtain permits and pay fees before riding dirt bikes and other motorized off-road vehicles on their property. It forbids any riding on plots of less than 5 acres and limits the number of people who can ride at a time on larger parcels.

A coalition of off-road riding and industry groups later sued Riverside County over the noise regulations, saying the rules conflicted with existing laws and placed harsh burdens on longtime landowners. The lawsuit was dismissed.

Off-road enthusiasts in San Diego County were not the only ones making noise over the proposed changes, Farace said.

"We got all types of different comments," he said. "Some people said, 'We think it should be worded this way, rather than that way.' And others said it was discriminatory to off-road vehicle advocates."

Representatives of two East County planning groups said at a hearing in May that the proposed ordinance was not strict enough, according to minutes of the meeting.

Members of the Potrero Community Planning Group approved a resolution in August saying the higher noise levels allowed under the proposed ordinance would "disturb neighbors and wildlife" and suggested the county conduct an environmental study on the proposed changes.

A Warner Springs resident said she was concerned the proposed ordinance would allow her neighbor to disturb the quiet in her neighborhood.

"It is my opinion that favoritism is being shown to those who want to ride off-road vehicles," Veronica Vanderlaan wrote in a letter to the county, complaining about the changes. "I am totally disappointed in the work that has been done on this new proposed noise ordinance."

One controversial aspect of the proposal is how sound will be measured by county code enforcement officers. The proposal would allow officers to measure sound levels in short periods of time, rather than sampled in a one-hour average.

That means that a short, loud noise could violate the ordinance. The sound level would be measured at the property line of the person who placed the complaint, Farace said.

The new measurement standard would allow "an additional enforcement tool," county officials wrote in a report to the Planning Commission.

However, the proposed ordinance, including the new measurement standard, would make it nearly impossible for off-roaders to enjoy their vehicles on their own property, opponents say.

"The proposed ordinance is a direct attack on the off-road community," Rick Moore, an El Cajon resident, wrote in a letter to the county.

Adams, the off-road enthusiast, said he would not be directly affected by the ordinance as he lives in Vista and goes to designated off-road recreation areas in Imperial County to ride his vehicles. However, he said he worried that off-roaders were being unfairly singled out by the ordinance.

Adams said he heard about the proposed changes through a newsletter from the San Diego Off-Road Coalition, a group that promotes off-roading and advocates on behalf of those who like to ride those vehicles.

The coalition did not return calls for comment.

The increase in the noise level to 85 decibels is an improvement to the original proposed ordinance, Adams said. But he would still like to see a measurement that includes an average over time, rather than quick measurements that will capture sounds at their loudest, Adams said.

"What is troublesome with this is that without averaging (noise measurements), no off-highway vehicles would pass a drive-by test," Adams said.

Contact staff writer Edward Sifuentes at (760) 740-3511 or esifuentes@nctimes.com.

CLARIFICATION: State has two standards

A story on the county's noise ordinance published Oct. 23 in most editions of the North County Times should have clarified that there are two state standards for off-road vehicles.

The first standard is a 96-decibel limit, which measures the sound level 20 inches from the exhaust as the vehicle stands still.

The second is an 82-decibel standard, which measures sound levels 50 feet from a moving vehicle.

The county proposes to model its ordinance using the second standard.