City of St. Louis Water Division Homepage


Curtis B. Skouby, P.E.
Director of Public Utilities

Curtis B. Skouby, P.E.
Water Commissioner

City of St. Louis Water Division
Dept. of Public Utilities
1640 S. Kingshighway
St. Louis, MO 63110

(314) 633-9000

Click Here for Directions




Tap Applications

The City of St. Louis Water Division is the sole agency allowed to make a tap into an existing water main. However, it is the responsibility of the customer to correctly size both the service tap and service line. Also, it is up to the contractor requesting the tap to do all excavating, to install the piping, valve and meter boxes or meter vaults, and to complete all backfilling and grade restoration. The contractor is to clearly mark the main at the location of the tap, also.

Water Service Connections are divided based upon the following categories:

  • Size
    • Small Service Connection: All service lines that are less than six (6) inches in diameter, and where the installed service line is a metal pipe, not cast iron or ductile iron pipe
    • Large Service Connection: All service lines that are six (6) inches or larger and any connections designated as a "Cast Iron Connection" by the Water Division
  • Use
    • General Supply (G.S.): Domestic Use only
    • General Supply Limited Service Sprinkler (G.S. LSS): Domestic Use and Limited Fire Protection
    • Automatic Sprinkler (A.S.): Fire Protection only
    • Combined (A.S.- G.S.): Domestic Use and Fire Protection
  • Number
    • Single: One service line for one use
    • Dual: Two taps on either side of a line valve, which are then interconnected
    • Through: Two or more taps on different water mains, with all of the service lines interconnected inside the property line
  • Piping
    • Single: One service tap supplying one service line crossing the property line
    • Split: One large service tap supplying two service lines crossing the property line, A.S. & G.S.


Small Service Connections

A small service connection is any connection with a service tap less than six (6) inches in diameter, and where the installed service line is a metal pipe, not cast iron or ductile iron. Current plumbing codes require a minimum of 1" copper service line. A small service line cannot be greater than 3" in diameter copper pipe. Small service connections shall only be a single number and single piping as outlined above. It can only be used for Fire Protection (A.S.), Domestic Use (G.S.) or Domestic Use and Limited Fire Protection (G.S. LSS).

Small service taps shall not be made on a 20" or larger water main unless that main is the smallest water main available, or the tap is approved by the Water Commissioner.

There are four sizes of small taps available:

  • 1" service tap is directly tapped into all mains 6" and larger
  • 1 1/2" service tap requires a tapping saddle for 6" water mains, is directly tapped into larger mains
  • 2" service tap requires a tapping saddle for 6" and 8" water mains, is directly tapped into larger mains
  • 3" service tap will consist of two-2" taps, requires a tapping saddle for 6" and 8" water mains, is directly tapped into larger mains

Applications for small taps need to be made with the Distribution Section. They are located at 4600 McRee. The phone number for this department is (314) 633-9029.

When you visit to apply for your tap, you must bring a copy of your plumbing and excavation permits.

Large Service Connections

A large service connection is any connection with a service tap which is six (6) inches in diameter and larger, and any other connection that was designated as a "Cast Iron Connection" by the Water Division at the time it was installed. These are 3" and 4" connections made with cast iron or ductile iron piping.

Before the Water Division will begin work to install the tap, the Contractor applying for the tap will need to complete an application. Applications for large taps need to be made with the Estimator. This individual is located at 4600 McRee Avenue, and may be reached at (314) 633-9024.

The Water Division will only schedule the installation of the tap after all of the items listed below have been supplied to the Water Division. The application shall include all of the following items:

  • A check or money order payable to the "City of St. Louis Water Division" in the amount of the cost estimate for the service tap installation
  • Copy of the Excavation Permit from the Street Department
  • Copy of the Plumbing Permit from the Building Division
  • If a backflow prevention device is required, a copy of the purchase order or bill of sale for the backflow prevention device
  • Copy of an approved drawing stamped and signed by the Fire Marshall's Office (for fire connections) and/or the Plumbing Section of the Building Division (for domestic service connections)
  • Completion of an application for service from the City of St. Louis Water Division Customer Service Section

NOTE: The plumbing contractor's name that is referred to on tap applications shall appear on the plumbing and excavation permits. The check or money order made payable to the City of St. Louis Water Division shall be from either the plumbing contractor or the holder of the water service account.

For more information regarding this matter, please review our Service Connection Regulations.

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City of St. Louis Water Division