Backflow Preventer Plan Check


As one of the requirements prior to the issuance of a Plumbing Permit by Long Beach Development Services, a plumbing applicant must go through plan review with the Long Beach Utility Department (LB Utilities) for backflow prevention requirement(s).

Projects that shall require backflow include but not limited to the following:

  • Building with three stories or more
  • Facilities with below-ground grease interceptor on-site
  • Facilities generating hazardous chemicals on-site
  • Facilities with pump tied into waterline
  • Facilities generating any additional on-site hazards
  • Buildings or sites with dedicated irrigation system
  • Sites with recycled water use on-site

Minimum Backflow Preventer Plan Check Requirements

  • Full payment. Please make your check payable to Long Beach Utilities. For applicable fees, see LB Utilities' Rules & Regulations(PDF, 868KB) (View Appendix B, B1, Page 80)
  • For commercial applications, a reduced pressure (RP) backflow assembly is required. The device must be low-lead and be USC Foundation approved. Customers shall check approved devices at
  • For residential fire systems, either a low-lead Double Check (DC) backflow device or passive purge system is acceptable. Please refer to Table 604.1 of California Plumbing Code for suitable sprinkler piping material if passive purge system is proposed.
  • For irrigation, a pressure vacuum breaker (PVB) is accepted as follows:
    • No sprinkler shall be installed less than 12-inches below the device.
  • The plan shall show/include:
    • Plumbing plans showing:
      • Fixtures list showing projected demand (FU/gpm);
      • Proposed location of the backflow device labeling size, make, model, and if existing, serial number;
      • Backflow device manufacturer’s cut sheet.
  • Site plan showing:
    • Curb face and property line with labels;
    • Location of water meter with size; indicate if new or existing;
    • Indicate any existing meters to be kill-tapped;
    • Proposed location of backflow device.
  • The backflow preventer shall be located on property, but as close as practical to the water meter.
  • Backflow preventer devices located indoor shall be provided drainage per the latest California Plumbing Code. City of Long Beach Development Services will provide plan check for drainage of indoor devices.
  • The minimum water lateral and meter size shall be 1-inch for services with Residential Fire Sprinkler Systems.
  • After plumbing plan approval, any existing backflow prevention assembly must be:
    • Inspected/re-certified by the LB Utilities Meter Shop prior to water service turn-on.
    • Replaced with a low-lead unit (if the existing device is not low-lead) in the event water service is shut off for any reason. The replacement must be completed prior to water service restoration.

Additional Information

Water services 2” and smaller shall be sized per the CPC, latest edition.

  • In cases where sizing per CPC is not applicable, it is advised that demand (in gallons per minute / gpm) at the water meter should not exceed the following Meter Size and Lateral Size Criteria:
    • Safe Maximum Operating Capacity, (defined as 10 percent of usage, or 2 hours per day), and the Recommended Maximum Rate for Continuous Operation (per AWWA C700-15, Table 1):
Meter Size: 3/4″ 1” 1 ½” 2”
Safe Max (GPM):. 30 50 100 160
Continuous (GPM): 15 25 50 80

Lateral size 3/4” 1” 1 ½” 2” 3” 4” 6” 8” 10” 12”
Demand (gpm) 11 19 44 78 156 310 700 1250 1950 2800

Based on maximum velocity of 8 feet per second.

Lead Time

The typical processing time for your Backflow plan check request is approximately 7-10 business days.

Backflow Prevention Submittal

Please submit your plumbing plans that meet the requirements listed hereon through LB Utilities' online portal, Laserfiche, at the following link: