DDW-2024-012964

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144830 • Salt Lake City, UT 84114-4830
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF DRINKING WATER
Tim Davis
Director

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor

April 6, 2023

Jacob Sharp
Castle Dale Water System
P.O. Box 877
Castle Dale, Utah 84513

Subject: System-Specific Minimum Sizing Standards
Castle Dale, System #08001, File #12469

Dear Jacob Sharp:

Based on the water use data submitted to the Division of Water Rights (DWRi), the following
system-specific minimum sizing standards have been set for Castle Dale:

Peak Day Source Demand (gal/day/ERC) – 724 gal/day/ERC
Average Annual Demand (gal/yr/ERC) – 179,774 gal/yr/ERC
Equalization Storage (gal/ERC) – 493 gal/ERC
Fire Storage (gal) – 120,000 gal

These standards are effective as of the date of this letter. A summary of the water use data and
calculations used to set the minimum sizing standards is attached for your reference. The Division
plans to evaluate these standards every 3 years, or upon request.

Water System Background

Castle Dale is a community water system that provides water for indoor use to a population of
approximately 1,650 people. Water for outdoor use is provided by a separate irrigation system.

Jacob Sharp
Page 2 of 3
April 6, 2023

Minimum Sizing Standard Background

Per Utah Code 19-4-114, the information needed for the Division of Drinking Water (the
Division) to set system-specific minimum sizing standards may be based on water use data
submitted to the DWRi, or alternatively, a community water system can submit an engineering
study to the Division if the water system’s water use data is not representative of future use or the
water system does not yet have actual water use data.

Actual water use data was available through DWRi and an engineering study was not submitted to
the Division for review. Therefore, the Division analyzed the submitted DWRi water use data and
sent a draft summary of the resulting system-specific minimum sizing standards to you on March
16, 2023. Updates were made and you replied on April 3, 3023 to verify the draft sizing standards
are representative. Therefore, the Division is setting system-specific minimum sizing standards for
Castle Dale.

The calculated variability for the Peak Day Demand was originally 40%. This was revised to 20%
as allowed by Division policy.

Water Use Data Definitions

Peak Day Source Demand is the total flow into a public water system to meet the demand of the
water system on the day of highest water consumption in a calendar year.

Average Annual Demand is the total quantity of drinking water flowing into a public water system
within a calendar year.

Total Equivalent Residential Connections (ERCs) term represents the number of residential
service connections and the number of equivalent residential connections for non-residential
connections (commercial, industrial, institutional connections).

Minimum Equalization Storage requirement is a volume that is equivalent to the amount of water
needed to meet the average day culinary demand for public water systems. Equalized storage per
ERC is calculated by dividing the Average Annual Demand per ERC data by the number of
operational days in a year.

Fire Storage was set based on information from you based on your local fire authority
requirements on March 30, 2023.

Storage Capacity

Based on your system’s storage facilities and the storage minimum sizing requirement established
in this letter, your system is compliant with the minimum storage capacity requirements.
Jacob Sharp
Page 3 of 3
April 6, 2023

Source Capacity

The Division has documentation of established safe yields for all your system sources. Using total
system-wide safe yields and the source minimum sizing requirement established in this letter
indicates your water system is compliant with minimum source capacity requirements.

If you have any questions regarding this letter, please contact Julie Cobleigh, of this office, at
[phone], or Michael Newberry, Engineering Manager, at [phone]. 

Sincerely,

Michael Newberry, P.E.
Engineering Manager

JJC/mrn/mdb

Enclosures
1. Utah Department of Environmental Quality Division of Drinking Water Minimum Sizing Standards
Summary Report

cc: Orion Rogers, Southeast Utah Health Department, [e-mail]
Russell Seeley, SE District Engineer, [e-mail]
Jacob Sharp, Castle Dale, [e-mail]
Julie Cobleigh, Division of Drinking Water, [e-mail]
Ted Black, Office of the State Fire Marshal, [e-mail]

DDW-2023-005705

Utah Department of Environmental Quality
Division of Drinking Water
Minimum Sizing Standards
Date Standard Effective: Tue Apr 04 12:40:39 MDT 2023
Peak Day Source Demand per ERC (gal/day): 725
Average Annual Demand per ERC (gal/year): 179,774
Equalization Storage per ERC (gal/day): 494
CASTLEDALE PWS ID: UTAH08001
Admin Name: JACOB SHARP
Address: P.O. Box 877
City, State, Zip: Castle Dale, UT 84513
Phone: [phone]
Email: [e-mail]
System Type: Community
Population: 1,650
MINIMUM SIZING STANDARD
MINIMUM SIZING STANDARD CALCULATIONS VARIABILITY
Data from these reporting years: 2020, 2021, 2022
Peak Day Source Demand per ERC (gal/day): 604
Average Annual Demand per ERC (gal/year):
164,478 Equalization Storage per ERC (gal/day): 451
x
x
x
(1 + 0.2)
(1 + 0.093)
(1 + 0.095)
=
=
=
724
179,774
493
DWRi WATER USE DATA REPORTED
Equalization per ERC (gal): 494
Existing Storage (gal): 1,000,000
ERCs: 876
Required Storage w/o Fire Flow: 432,744
Required Fire Storage (gal): 120,000
Required Storage w/Fire (gal): 552,744
Storage Deficiency: 0
Storage Deficiency (%): 0.0
No Storage Deficiency
Peak Day Source Demand per ERC (gpm): 0.5
Existing Source Capacity (gpm): 1,050
ERCs: 876
Required Resource Capacity (gpm): 438
Source Deficiency: 0
Source Deficiency (%): 0
No Source Deficiency
Year Peak
Day
Source
Demand
(gal/day)
Average
Annual
Demand
(gallons)
ERCs Peak
Demand
per ERC
(gal/day)
Avg
Annual
Demand
per ERC
(gal/year)
Equaliza
tion
Storage
per ERC
(gal/day)
OP
Days
2022 358,436 125,090,940.39 831 431 150,531 412 365
2021 485,517 132,240,111.33 804 604 164,478 451 365
2020 485,517 134,188,700.31 876 554 153,184 419 366
Variability:0.09 0.2 0.093 0.095
Year Peak Month Average
(gal/day)
Peak Month Average
per ERD (gal/day)
Ratio of PD/ERC to
Peak Month Avg/ERC
2022 311,240 375 1.15
2021 415,197 516 1.17
2020 331,001 378 1.47
CAPACITY CALCULATIONS FOR STORAGE
CAPACITY CALCULATIONS FOR SOURCES
SYSTEM STORAGE AND SOURCE INVENTORY
Storage ID Storage Name Effective Volume (GAL)
ST001 CASTLE DALE TANK ST001 500,000
ST002 LANDFILL TANK ST002 500,000
Storage Totals: 1,000,000 GAL
Source ID Source Name Flow Rate (GPM)
TP001 STRAIGHT CANYON MEMBRANE WTP
Source Totals: 1,050 GPM
1,050
*WTP serves both Orangeville and Casteldale (278 gpm and 438 gpm source
requirements for a total of 718 gpm)