DDW-2024-007019

April 2, 2024

Attn: Director
Utah Division of Drinking Water
P.O. Box 144830
Salt Lake City, UT 84114-4830

Re: Minimum Separation Standards for Water and Sewer Lines, Salt Lake City Water System
Project No. 513505602

To whom it may concern,

Utah Administrative Code R309-550-7 requires that the horizontal distance between water lines and
sewer lines be 10 feet. This code also requires that a water main be at least 18-inches above a sewer
main where a water main and sewer line must cross. This letter is a formal exception request for the
minimum separation requirements between water and sewer lines for the project titled Virginia Street
– South Temple to 11th Ave Water Line Replacement.

SLC Public Utilities (DPU) is replacing about 1,200 feet of the existing 8” Ductile Iron Pipe (DIP)
water line along Virginia Street from Crestline Circle to 11th Ave. The proposed water main will be a
majority 8-inch Class 52 CML DIP water main with push on joints, with some 12” DIP. It runs parallel
to the existing water mains and the proposed water main is located within the existing asphalt width.
The existing asphalt is between 32-35 feet wide. The proposed water main will also run parallel to
existing 8-inch sewer mains owned by SLCDPU. The existing sewer information is listed below. All
sewer pipe has gasketed joints and are gravity lines:

1. Virginia St – vitrified clay pipe installed in 1992, and CIPP lined in 2024. It was videoed in March
2024 and is in good condition.
2. Popperton Park Way - PVC pipe installed in 1993. It was videoed in March 2022 and is in fair
condition.

Groundwater is expected to be more than 6.5 feet deep. We do not expect to encounter groundwater
during construction. The soil in the area are expected to be very cobbly loamy sand. Static water
pressures in the area range from 100- 150 psi.

We have varied the location of the proposed water line to maximize horizontal distance and vertical
separation distance from the sewer line while still keeping the proposed water line within the asphalt
width. The new water main will be between 6 feet and 10 feet away from the sewer for the entire
project. The below locations are where we are not meeting this rule:

1. Virginia St – ~100 LF of new water line will be below the existing sewer pipe. The new water line
will be 12” below the existing sewer at a perpendicular pipe crossing. See sheet PP-2.
2. 11th Ave - ~85 LF of new water line will be below the existing sewer pipe. The new water line will be
18” below the existing sewer at a perpendicular pipe crossing. See sheet PP-4.

All dimensions are measured from outside of pipe to outside of pipe.

ERIN MENDENHALL
PUBLIC UTILITIES
Page 2

The minimum vertical separation cannot be met due to existing utilities constraints and the existing
sewer depth. There is not available space to loop the water line above the existing sewer line without
conflicting with other existing utilities, namely (2) 10 -inch Chevron crude oil lines. The existing sewer
depth measures 7.5-feet from top of asphalt to top of SS pipe. If we find a way to field adjust our water
main location and create more separation between sewer and water during construction, DPU will
take advantage of this opportunity.

Our mitigation measures at the locations where we are not meeting the rule include the following:

• We plan to install the new water main in a new, separate trench, leaving undisturbed material
horizontally between the two utilities. We plan to install the new water main with a minimum
horizontal separation of 6-feet (measured from outside of pipe to outside of pipe).

• Install restrained joint pipe and restrained joints along the length of water line that will be
installed below the existing sewer. This would look like TR Flex Restrained joint pipe (or
approved equal) at pipe & pipe connections, and Mechanical Joints with Megalug Followers at
pipe and fitting connections. This is intended to ensure restrained joints and prevent
longitudinal separation at joints.

• The existing sewer is in fair-good shape. Some of the existing sewer is CIPP lined.

The proposed mitigation measures prevent longitudinal separation in the pipe joints. They provide
additional protection against infiltration into the water system, which meets the intent of the rule. Salt
Lake City DPU recommends accepting these proposed water line designs. If you have any questions,
please call Courtney Hamer at 801-483-6843.

Sincerely,

___________________________
Teresa Gray
Water Quality and Treatment Administrator
Salt Lake City Department of Public Utilities
801-483-6744

Cc: Courtney Hamer – SLCPDU
Natalie Moore - SLCDPU

Attachments: Plan Sheets PP-2 and PP-4