Methane is a hidden challenge for real estate projects. When you are planning a project in Southern California, it is a serious concern. For example, in Los Angeles, you can’t ignore methane gas.

You might not see it or smell it. But methane can sneakily accumulate under the ground. Typically, it is made from old oil wells, decomposed organic matter or outhauls. If unchecked, it turns into a serious safety issue as well as a regulatory challenge.

The City of Los Angeles, LADBS, has designated special zones. These zones are called “the Methane zone or Buffer zone”. In these zones, methane testing is mandatory. If your property falls within one of these Zones, you’ll need to hire certified consultants. 

The consultant would run detailed tests and possibly install a mitigation system. These are necessary steps before you can get a building permit.

This article explains everything you need to know about methane testing and mitigation. It covers everything from how it works to what it might cost. The article addresses the concern of how to stay compliant in the process.

Methane is an invisible gas, created naturally over time. When trapped underground, it may not cause immediate harm. 

But when you build on top, especially with slab-on-grade or basement foundations, it is harmful. This gas can migrate into the building and collect in enclosed spaces. It forms in places like:

• Former oil fields
• Decaying organic-rich soils
• Abandoned landfills or oil wells

This creates two major risks:

1. Health risks due to long-term exposure.
2. Explosion risks occur due to gas concentration rising to dangerous levels.

Due to this, LADBS, along with local governments, has set strict methane mitigation guidelines. This is a practice in places like Long Beach and Signal Hill. These guidelines are helpful to keep projects safe.

Working rules relating to methane may be applicable near oil plants. Same again when you are redeveloping a brownfield. Methane testing will normally be essential in most cases. The locations include underground gas, which is normally risky. 

To find out more, please visit the California Geological Survey. They provide elaborate publications and risk maps. These aids make you learn about the regional methane hazards. Take them with you when planning and site review.

Not every project needs methane testing. But if your site is located in a Methane Zone or Buffer Zone, testing becomes mandatory before permits can be approved.

There are many tools to check the availability of methane gas. The easiest way to check is using the ZIMAS portal. This is an official property info tool run by the City of Los Angeles. 

You can also explore methane mapping through different platforms. For example, GeoForward which offers detailed GIS-based methane hazard layers.

Methane testing is generally required if your site:

• Lies within the mapped methane or buffer zones
• It is near active or abandoned oil wells
• It is close to landfills or former industrial zones
• It involves deep excavation (e.g., basements, pile foundations)

Methane testing may be required even in the case your project is located in an unregulated zone. Caltrans and metro LA also have environmental instructions. 

These are commonly imposed on public infrastructure projects. Again, be sure to go by local and state agency standards. Accomplish this as one of the first steps in your planning.

After there is a need to test, a certain process is launched. It has definite steps. All the steps matter, and they are all safety and compliance-related. It begins immediately after the official activation of the testing. This is how it works step by step.

Step 1: Site Evaluation

Your team or environmental consultant begins with a GIS-based zoning check. You can use tools like ZIMAS or GeoForward. If methane risk is confirmed, fieldwork begins.

Step 2: Engagement of Certified Consultant 

An LADBS-certified methane testing consultant must also carry out testing. The plan will be checked, and these uncertified reports will not pass. 

Step 3: Install Probes to Monitor

Probes or boreholes are installed at varying depths by crews. These are of the order of 5 to 10 feet deep. They are put along the periphery of the project location. This is done based on the condition of the soil. Power drilling can be light drilling, hand augers or vacuum extraction.

Step 4: Gas Monitoring

The site is monitored for 24 to 48 hours to record real-time gas accumulation. Passive and active sampling techniques may be used.

Step 5: Lab Analysis & Reporting

Samples are sent to a certified lab to measure:

• Methane gas (per cent by volume)
• Oxygen levels
• Carbon dioxide
• Flammable vapor presence

A formal report is then generated. This report is submitted to LADBS (or your local building department). The report classifies your site under a hazard level from I to V.

Your mitigation requirements depend on the methane hazard level assigned to your site:

These levels are described in the LADBS Methane Mitigation Standards. Higher hazard levels require more complex and costly systems.

If mitigation is required, your consultant will design a customized system for your building. That plan must be submitted for review and approval—just like your building plans.

A methane mitigation system may include:

Sub-Slab Barriers

A high-duty plastic liner is employed. It is normally composed of HDPE. The liner rests somewhere below the foundation slab. It is meant to seal the infiltration of gas.

Ventilation Systems

• Passive systems rely on natural airflow through vent pipes.
• Active systems use fans or blowers to remove gas before it enters the structure.

Sealed Utility Penetrations

All pipes, conduits, and wires that pass through the foundation must be gas-tight. LADBS requires specialized seals to prevent leaks.

Methane Detectors and Alarms

Gas detection sensors are installed within the building. These sensors alert occupants or shut off utilities if methane is detected.

Sub-Slab Monitoring Ports

Small ports beneath the slab allow for continued methane testing after the building is complete. After installation, you should get your system checked up. For this, you can hire a LADBS-licensed Deputy Methane Inspector. 

This is to be followed by this inspection before final occupancy consent. 

Methane testing and mitigation can affect your budget and schedule, so plan accordingly.

• Testing Costs: $3,000 to $10,000 per site
• Mitigation System Costs: $20,000 to $150,000+ for Level IV–V systems
• Timeline: 2 to 6 weeks for testing, design, review, and installation

These should be some of the things included early in your project pro forma. This may help avoid schedule delays and cost overruns. Many designers consider methane compliance during initial planning. They tend to have it as part of their Phase I and Phase II Environmental Site Assessment (ESAs). 

The DEI California Department of Toxic Substances Control (DTSC) has additional advice. Their assets assist in the incorporation of methane planning in brownfield and redevelopment schemes.

You may be exempt from methane mitigation if:

• Your property is outside methane zones
• Testing results return a Level I hazard
• The structure is temporary, unoccupied, or open-air
• A vented crawl space allows natural dissipation

However, all exemptions must be verified and documented by a certified consultant. The report must be submitted to the local agency and placed on record. Don’t rely on assumptions—get it in writing.

To stay ahead of potential methane issues, follow these best practices:

• Use ZIMAS or GeoForward early in site due diligence
• Include methane testing in your environmental review checklist
• Hire LADBS-certified consultants from the beginning
• Budget for both testing and mitigation in your early financial models
• Add the methane review to your permit approval timeline
• Schedule Deputy Inspector reviews well in advance

Methane review is significant concerning large concepts of infrastructure projects. The same can be applied to the developments that are public-private. See the Caltrans Standard Plans regarding methane. 

In addition, look at the environmental planning terms of metro LA. This makes sure it is in line with the standards of the state and region.

Methane testing and mitigation are very crucial. It is the case in Southern California in particular. Methane zones are common in occurrences such as Los Angeles. These are also areas which are keenly followed. 

It is better to be proactive. The first thing to look at is to see whether your location falls within a methane zone. Use licensed specialists. Plan certain mitigation. It is possible to save money, time, and stress by doing it. Above all, it guards your building. It also ensures the protection of people. 

Do you have a multi-unit? Or an office block? Or perhaps infrastructure? Regardless of the type, make early preparation to be compliant with methane. Use it as one of the major components of your project.