DDW-2024-011476

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
October 16, 2023

Via Email: [e-mail]
Thomas G Isom
Erda Acres Water Company
PO BOX 11
Tooele, Utah 84074

Subject: System-Specific Minimum Sizing Standards—Final Determination
Erda Acres Water Company, System #23053, File #12367

Dear Thomas Isom:

DETERMINATIONS

Based on the findings set forth below, the Division of Drinking Water (the Division) hereby
establishes the following system-specific minimum sizing standards for Erda Acres Water
Company (the System):

Peak Day Source Demand (gallons/day/ERC) – 3,146
Average Annual Demand (gallons/year/ERC) – 381,562
Equalization Storage (gallons/ERC) – 1,043
Fire Storage (gallons) – 180,000

Introduction

Pursuant to Utah Code Section 19-4-114, the Director of the Division (Director) is required to
establish system-specific minimum sizing standards based on, among other factors, water use data
submitted to the Division of Water Rights (DWRi). The Director’s determinations may also be
based on engineering analyses and other evidence if this is available. This final determination
letter is addressed to you in your capacity as the Administrative Contact for the System. The
Director has delegated the responsibility for making system-specific minimum sizing standards
under Utah Code Section 19-4-114 to the Engineering Manager for the Division.

Prior to issuing this final determination letter, the Division analyzed applicable DWRi water use
data and sent a draft summary of the Division’s proposed system-specific minimum sizing
Thomas G. Isom
Page 2 of 4
October 16, 2023

standards to the System on September 11. 2023. The Division allowed for 30 days for the System
to review the draft system-specific minimum sizing. The System provided comments on
September 12, 2023. The Division has taken these comments into account in reaching this final
determination of the system-specific minimum sizing standards for the System. A summary of the
water use data and calculations the Division used to make these determinations is attached as part
of the administrative record.

Water Use Data Definitions

As used in this Final Determination, the following terms have the following meanings:
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 the 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.

Water System Background Facts

The System is classified as a community water system with a population of approximately 950
people. The system serves 315 residential connections and 4 commercial connections. Each
connection is supplied by the distribution network and connected facilities. The system has two
wells, one chlorinator, one pump station, and two storage tanks.

System-Specific Minimum Sizing Standards—Background

Under Utah Code Section 19-4-114, the legislature required that the Director establish minimum
sizing standards on a system-specific basis instead of statewide, as the Division has done in the
past. System-specific determinations need to be based on system-specific information. The code
allows the Director to rely on water use data submitted to DWRi. Alternatively, a community
water system may perform and 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. In this matter, actual water use data was available through DWRi, and an
engineering study was not submitted to the Division for review. Therefore, the Division has relied
upon DWRi information and other relevant data.

Thomas G. Isom
Page 3 of 4
October 16, 2023

Additional System-Specific Basis for Determinations

The Division established Fire Storage requirements based on information from the North Tooele
Fire District on October 2, 2023. The System requested the Division to use a variability factor for
the Peak Day Demand/Equalization Storage of 0%.

Storage Capacity

Based on the System’s storage facilities and the storage minimum sizing requirement established
in this letter, the Director hereby determines that the System is compliant with the minimum
storage capacity requirements.

Source Capacity

The Division has adequate documentation of established safe yields (wells) for all the System’s
sources. Using total system-wide safe yields and the source minimum sizing requirement
established in this letter indicates that the System is compliant with minimum source capacity
requirements.

Effective Date

The determinations made in this letter are effective immediately and will become final 30 days
from the date of this letter unless the System files a contest as provided below.

Notice of Right to Contest

The Director has determined this determination made under Section 19-3-114 qualifies as a
“permit order” within the meaning of Utah Code Section 19-1-301.5(1)(f). See Utah Code § 19-1-
301.5(1)(e) (defining “permit” to include a “plan” or “other administrative authorization”).

The System may contest any determinations made herein by delivering a notice of contest to the
Director. The notice of contest must be in writing and must be delivered to the Director on or
before 30 days after the date this letter is signed. There is no particular form for the notice of
contest, but it must include the System’s reasons and rationale for the contest. The Director’s
address for purposes of submitting a notice of contest is as follows:

U.S. Mail
Division of Drinking Water
Attention: Director
P.O. Box 144830
Salt Lake City, UT 84114-4830

Email
A notice of contest may be submitted to the Director by email, provided, however, that the
Director confirms receipt of the email. The Director’s email address is:
Thomas G. Isom
Page 4 of 4
October 16, 2023

[e-mail]. The email submission must be received by the Director before the
expiration of the contest deadline.

If the System files a timely notice of contest, the Director will evaluate the matter and attempt to
resolve the matter through negotiations. If the Director is not able to resolve the matter, the
Director will issue a final agency action regarding the contest. At that point in the process, the
System shall have the right to seek further internal agency and judicial review pursuant to Utah
Admin. Code R305-7 and Utah Code Section 19-1-301.5.

Right to Request Reconsideration

The Director plans to evaluate the determinations made herein every three years. However, this
requirement is not mandatory. At any time, a water system whose system-specific minimum
sizing standards have been established by the Division under Section 19-4-114 may request
reconsideration of the Director’s determinations by submitting a written request. A request for
reconsideration shall be submitted to the Director in the same manner as a notice of contest
provided above.

Conclusion

If the System management has any questions regarding this letter, please contact Chris Martin, of
this office, at [phone], or me at [phone].

Sincerely,

Michael Newberry, P.E.
Permitting and Engineering Support Manager

CM/mrn/mdb

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

cc:
Bryan Slade, Tooele County Health Department, [e-mail]
Thomas G. Isom, Erda Acres Water Company, [e-mail]
Alan Clark, Erda Acres Water Company, [e-mail]
Chris Martin, Division of Drinking Water, [e-mail]
Buck Peck, North Tooele Fire District, [e-mail]
Ted Black, Office of the State Fire Marshal, [e-mail]

DDW-2023-039351
Utah Department of Environmental Quality
Division of Drinking Water
Minimum Sizing Standards

Date Standard Effective: Thu Oct 12 09:33:48 MDT 2023
Peak Day Source Demand per ERC (gal/day): 3,146
Average Annual Demand per ERC (gal/day): 381,562
Equalization Storage per ERC (gal/day): 1,043
ERDA ACRES WATER CO PWS ID: UTAH23053
Admin Name: THOMAS G ISOM
Address:
City, State, Zip: ,
Phone: [phone]
Email: [e-mail]
System Type: Community
Population: 950
MINIMUM SIZING STANDARD
MINIMUM SIZING STANDARD CALCULATIONS VARIABILITY
Data from these reporting years: 2020, 2021, 2022
Peak Day Source Demand per ERC (gal/day): 3,146
Average Annual Demand per ERC (gal/year): 381,562
Equalization Storage per ERC (gal): 1,043
x
x
x
(1 + 0.0)
(1 + 0.0)
(1 + 0.0)
=
=
=
3,146
381,562
1,043
DWRi WATER USE DATA REPORTED
Equalization per ERC (gal): 1,043
Existing Storage (gal): 1,000,000
ERCs: 315
Required Storage w/o Fire Flow: 328,545
Required Fire Storage (gal): 180,000
Required Storage w/Fire (gal): 508,545
Storage Deficiency: 0
Storage Deficiency (%): 0.0
No Storage Deficiency
Peak Day Source Demand per ERC (gpm): 2.18
Existing Source Capacity (gpm): 1,175
ERCs: 315
Required Source Capacity (gpm): 687
Source Deficiency: 0
Source Deficiency (%): 0.0
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/day)
Equaliza
tion
Storage
per ERC
(gal/day)
OP
Days
2022 788,559 95,389,621.74 315 2,501 302,537 829 365
2021 681,028 93,848,346.51 305 2,233 307,771 843 365
2020 922,158 111,854,872.77 293 3,146 381,562 1,043 366
Variability:0.075 0.0 0.0 0.0
Year Peak Month Average
(gal/day)
Peak Month Average
per ERD (gal/day)
Ratio of PD/ERC to
Peak Month Avg/ERC
2022 675,562 2,143 1.17
2021 606,818 1,990 1.12
2020 664,841 2,268 1.39
CAPACITY CALCULATIONS FOR STORAGE
CAPACITY CALCULATIONS FOR SOURCES
SYSTEM STORAGE AND SOURCE INVENTORY
Storage ID Storage Name Effective Volume (GAL)
ST002 1.0 MILLION GALLON TANK 1,000,000
Storage Totals: 1,000,000 GAL
Source ID Source Name Flow Rate (GPM)
WS002 WELL #2 NELSON 700
WS003 WELL #3 CAMPBELL 475
Source Totals: 1,175 GPM