Where we work
Water Engineering
Water engineering for California developments: Division of Drinking Water permits, SB 1263 reports for new systems, storage and distribution design.
What we do in California
Water engineering for California developments
MES designs water systems for developers, utilities and municipalities. That covers supply, treatment, storage, pumping and distribution.
For a new development, the first question is whether an existing water system can serve the site. The answer shapes the rest of the design.
How drinking water permitting works in California
The State Water Board's Division of Drinking Water (DDW) permits public water systems. A new system needs a domestic water supply permit. A major change to an existing system needs a permit amendment.
In many counties, the county environmental health department acts as a Local Primacy Agency. It regulates public water systems with fewer than 200 service connections.
A proposed new public water system starts with a preliminary technical report under SB 1263. It must reach the State Water Board at least six months before construction of any water-related improvement.
The report looks at public water systems within three miles and whether the project could connect to one. It also tests whether the supply can meet 20 years of demand.
Design follows the California Waterworks Standards in Title 22 of the California Code of Regulations. The local water provider and fire authority set their own connection and fire flow rules on top.
Our work in California
Our completed California projects so far are site civil plans, typically with a utility plan. Our water system design work is in other states, such as groundwater treatment and distribution for a Colorado district.
Common questions
Can a new development build its own water system in California?
Sometimes. The State Water Board can deny a permit for a new system when an existing system could serve the area and the new system is unlikely to supply safe, affordable water over time. That is why the SB 1263 report comes first.
Who regulates small water systems?
DDW regulates systems with 200 or more service connections. Smaller systems are regulated by the county where the county is a Local Primacy Agency, and by DDW everywhere else.
Does California allow direct potable reuse?
Yes. The State Water Board adopted direct potable reuse rules in December 2023. Read our summary of the rules.
Talk to an engineer
Tell us about your project.
An engineer reads it
Not a salesperson. Someone who can tell you whether the pathway is real.
You get a first answer
Your options, the agencies involved and the questions that decide cost and schedule.
You decide
No commitment to have the first call.
Prefer the phone? (214) 833-6748