DDW-2025-010312

October 24, 2025
Sent via Email Only
Jake Ferguson
South Davis Water District
407 West 3100 South
Bountiful, Utah 84010
[e-mail]
Subject:Plan Approval, Val Verde PFAS Mitigation Water Line Project (DS001);
South Davis Water District, System #06009, File #25088
Dear Jake Ferguson:The Division of Drinking Water (the Division) received the plans and specifications for the proposed Val Verde PFAS Mitigation Water Line project from our consultant,
Brian Naylor, P.E. with ESI Engineering on September 10, 2025. Written review comments were provided to your consultant on September 24, 2025. The Division received the revised plans
and specifications on October 21, 2025. This project has met the conditions for receiving a plan approval.
Our understanding of the project is the installation of a 6-inch diameter PVC C900 transmission line to connect the north end of the water system which is fed by Bona Vista Well (WS008)
to the south end which is fed by Val Verde Well (WS009). The Val Verde Well (WS009) PFAS concentration levels are up to 5.3 ppt for PFOA and 14.0 ppt for PFHxS.
The project is located on 100 East between 3300 South and 3517 South. The south system that runs between the residences 3517 South 100 East and 3531 South 100 East has PFAS levels that
are too high for upcoming Federal regulations. The project will include the installation of a sampling station on the south system downstream from the mixing location.
We have completed our review of the plans and specifications, stamped and signed byBryan Naylor, P.E.dated October 1, 2025, and find they basically comply with the applicable portions
of Utah’s Administrative Rules for Public Drinking Water Systems in R309. On this basis, the plans for the Val Verde PFAS Mitigation Water Line Project are hereby approved.
This approval pertains to construction only. An Operating Permit must be obtained from the Director before the water line may be put in service. A checklist outlining the items required
for operating permit issuance is enclosed for your information.Blending PlanAt the time of the operating permit application, a blending plan approval must be submitted and approved.
The blending plan must include the requirements detailed in the enclosed “Blending Plan Submission Checklist.” If you have questions regarding the Blending Plan, please contact Sarah
Romero, P.E., at [e-mail] or permits from the local authority or the county may be necessary before beginning construction of this project. As the project proceeds,
notice of any changes in the approved design, as well as any change affecting the quantity or quality of the delivered water, must be submitted to the Division. We may also conduct interim
and final inspections of this project. Please notify us when actual construction begins so that these inspections can be scheduled.
This approval must be renewed if construction has not begun or if substantial equipment has not been ordered within one year of the date of this letter.
If you have any questions regarding this approval, please contact Julie Cobleigh, P.E., of this office, at [phone], or me at [phone].
Sincerely,
Michael Newberry, P.E.
Permitting and Engineering Support Manager
JJC/mrn/mdbEnclosures –Operating Permit Checklist, Blending Plan Submission Checklistcc: Jay Clark, Davis County Health Department, [e-mail] Ferguson, South Davis
Water District, [e-mail] Chandler, Horrocks, [e-mail] Naylor, ESI Engineering, [e-mail]
Julie Cobleigh, P.E., Division of Drinking Water, [e-mail]
David Kruse, Division of Drinking Water, [e-mail]
Sarah Page, Ph.D., Division of Drinking Water, [e-mail]
Sarah Romero, P.E., Division of Drinking Water, [e-mail] 06009 25088 PA
Utah Division of Drinking Water ― Checklist for Issuing Operating PermitsWater System Name:System Number: Project Description:File Number:
Items 1 through 8 below must be submitted to the Division and found to be acceptable prior to operating permit issuance (unless a water line project meets the requirements of R309-500-7
and is not required to obtain an Operating Permit).
Distribution lines (not including in-line booster pump stations) requiring Plan Approval may be placed into service prior to submitting all of the following items and receipt of Operating
Permit if the water system has received items 1 and 4 below.☐1.Certification of Rule Conformance by a professional engineer (P.E.) that all conditions of Plan Approval were accomplished,
and if applicable, changes made during construction were in conformance with rules R309-500 through 550☐2.As-built or record drawings incorporating all changes to approved plans and
specifications (unless no changes were made to the previously approved plans during construction)☐3.Confirmation that as-built or record drawings have been received by the water system☐4.Satisfactory
bacteriological samples as evidence of proper disinfection and flushing in accordance with the appropriate ANSI/AWWA standards:
☐ANSI/AWWA C651-14 AWWA Standard for Disinfecting Water MainsTwo consecutive sample sets at least 16 hours apart, none positive (e.g., every 1,200 feet, end-of-line, each branch)☐ANSI/AWWA
C652-11 AWWA Standard for Disinfection of Water-Storage FacilitiesOne or more samples, none positive☐ANSI/AWWA C653-13 AWWA Standard for Disinfection of Water Treatment PlantsTwo consecutive
samples per unit, none positive, no less than 30 minutes apart☐ANSI/AWWA C654-13 AWWA Standard for Disinfection of WellsTwo consecutive samples, none positive, no less than 30 minutes
apart☐5.Water quality data, where appropriate [For example, include raw and finished water data that demonstrate satisfactory performance of the treatment facility; sample should be
taken from a storage tank for residual volatile organic compounds after tank interior re-coating; etc.]☐6.If applicable, all other documentation that may have been required during the
plan review process☐7.If applicable, confirmation that the water system owner has received the O&M manual for the new facility☐8.If applicable, location data of new storage tank, treatment
facility, or source
PFOA and PFOS Blending Plan Submission Checklist
Blending is a mitigation strategy where multiple water sources are combined to produce a flow with a contaminant concentration below the Maximum Contaminant Level (MCL). Accurate flow
monitoring and understanding the raw water chemistry is a vital part of a blending plan.
To start a blending plan review, fill out the Division’s Project Notification Form, found at deq.utah.gov/drinking-water/general-plan-approval-process, and email the form and all supporting
documents to [e-mail]. An engineer will then be assigned to review your proposed blending plan and may request additional supporting documentation.
At a minimum the blending plan proposal must include the following items:
Describe source issues, contaminant, contaminant level, MCL, and acute or chronic health impact. Include the dates that the sources are in use. Specifically, when/if the high PFOA/PFOS
contaminant source is used seasonally or year-round.
Describe the proposed strategy to meet the MCL. This includes flow rates of all sources used and the resulting proposed blend. Describe where the water sources originate and mechanically

how the blending occurs.
Describe how to monitor compliance with the MCL moving forward. Include specific locational information for where the water will be blended and how samples will be taken from this location.
Final blended concentrations shall be below the MCL before the first service connection.
Describe the blending strategy to ensure that the source with the high contaminant levels will always be blended to below the MCL. Are the sources operated using SCADA programming, or
will the wells be turned on manually? Please include SCADA schematics where applicable.
Provide historical data for the contaminant of concern and include average and maximum sample values for that analyte.
Calculate the contaminant concentration of the blended stream using the following formula:
Where:
CB = contaminant concentration of blended stream (mg/L)
C1 = contaminant concentration of Source 1 (mg/L)
C2 = contaminant concentration of Source 2 (mg/L)
Q1 = Flowrate of Source 1 (gpm), and
Q2 = Flowrate of Source 2 (gpm)
See EPA’sArsenic Treatment Technology Evaluation Handbook for Small Systems, pg 14, for more information on calculating concentrations, or determining required flowrates of sources.
For PFOA and PFOS contaminants, it is required for the blending operations to be designed to target final concentrations below the MCL of 4.0 ppt; however, the Division of Drinking
Water (the Division) recommends that blending operations be designed to target final concentrations below the trigger level of 2.0 ppt.
Monitoring Requirements Associated with PFAS Blending Plans
Following blending plan approval the following monitoring requirements will apply:
Quarterly samples for the targeted contaminants at both the source high in the contaminant and the blending compliance point,
If after four consecutive quarters of sampling, the results at the blending plan compliance point are below applicable MCLs, the water system may request that the monitoring frequency
be reevaluated.
Water Use Reporting
The system will be required to keep accurate monthly water usage data of the blended sources. The System will be required to compile all sample results and water usage data and submit
it in a quarterly report to the Division. The report is due by the 10th day following the end of the quarter (i.e., April 10, July 10, October 10, and January 10).