Wastewater Engineering

Wastewater engineering for California developments

MES designs wastewater systems for developments that need more than a simple sewer tap. That can mean a collection system, a lift station, a small treatment plant or a recycled water system.

We start with the disposal question. Where can the treated water go, and which permit fits that path?

How wastewater permitting works in California

The Regional Water Quality Control Board for the site issues most wastewater permits. A discharge to land gets waste discharge requirements (WDRs). A discharge to a river or other surface water gets an NPDES permit.

A small domestic system that treats under 100,000 gallons per day and disposes of it on land may qualify for the State Water Board's general order for small systems, Order WQ 2014-0153-DWQ.

Recycled water follows the Title 22 Water Recycling Criteria. The Division of Drinking Water must approve a Title 22 Engineering Report for every recycled water project. Some projects can then enroll under the general order for recycled water use, Order WQ 2016-0068-DDW.

Septic systems follow the State Water Board's OWTS Policy. Many counties carry it out through an approved Local Agency Management Program.

An industrial user that discharges to a city sewer may need a permit from the local sewer agency. Read about California industrial discharge permits.

Our work in California

Our completed California projects so far are site civil plans, not treatment plants. Our wastewater plant design work is in other states, such as a replacement 40,000 gpd plant for an RV park in Colorado.

Common questions

Do I need WDRs or an NPDES permit?

It depends on where the treated water goes. A discharge to land falls under WDRs. A discharge to surface water needs an NPDES permit. Read how to choose between WDRs and recycled water rules.

What is Order WQ 2016-0068-DDW?

It is the State Water Board's general order for recycled water use. It gives eligible projects a standard path instead of project-specific requirements. Read our guide to the order.

Who prepares a Title 22 Engineering Report?

An engineer registered in California with wastewater treatment experience. The report goes to the Division of Drinking Water and the Regional Board before the project starts. Read our Title 22 report guide.