DWQ-2025-004272

MONITORING AND SAMPLING FREQUENCY
GUIDANCE DOCUMENT
Utah Division of Water Quality
AUGUST 2024 (Updated May 2025)
Acronyms:
AOAC – Association of Official Analytical Chemists
ASTM – American Society for Testing and Materials
BOD5 – Biochemical oxygen demand
CBOD – Carbonaceous biochemical oxygen demand
CFR – Code of Federal Regulations
COD – Chemical oxygen demand
DO – Dissolved oxygen
DWQ – Utah Division of Water Quality
EPA – Environmental Protection Agency
MGD – Million gallons per day
NPDES – National pollutant discharge elimination system
POTW – Publicly owned treatment works
SM – Standard Methods
TDS – Total dissolved solids
TSS – Total suspended solids
TRC – Total residual chlorine
UAC – Utah Administrative Code
UPDES – Utah pollutant discharge elimination system
USGS – United States Geological Society
WET – Whole effluent toxicity
Introduction:
This document was developed to provide guidance to Utah Division of Water Quality (DWQ) staff for implementation of Monitoring and Sampling Frequency for the Utah Pollutant Discharge
Elimination System (UPDES) permit program pursuant to the federal National Pollutant Discharge Elimination System (NPDES) requirements and state water quality standards. This guidance
document was developed to increase consistency of monitoring frequencies among UPDES individual permits.
Disclaimer:
This document aims to provide guidance, but the permit writer will assess each UPDES permit issuance and renewal individually, considering the factors listed below in the Guidance Section.
The permit writers and DWQ Director have the authority to deviate from guidance when factors justify the need to do so.
Background:
Monitoring is performed by permittees to determine compliance with effluent limitations established in UPDES permits; establish a basis for enforcement actions; assess treatment efficiency;
and characterize influent, effluent discharges, and receiving waters.
Regulations requiring the establishment of monitoring and reporting conditions in NPDES permits are in Title 40 of the Code of Federal Regulations (CFR) 122.44(i), 122.48 and can also
be found in Utah Administrative Code (UAC) R317-8-4.1(10). Regulations in 40 CFR 122.44(i) and UAC R317-8-4.1(10) require permittees to monitor pollutant mass (or other applicable unit
of measure) and effluent volume; and to provide measurements using test methods established in 40 CFR Part 136.
Regulations in 40 CFR 122.48 stipulate that all NPDES (UPDES) permits must specify requirements concerning the proper use, maintenance, and installation of monitoring equipment or methods.
UPDES permits must also specify the monitoring type, intervals, and frequency sufficient to yield data that are representative of the activity.
Guidance:
Regulations require permittees discharging pollutants to waters of the State to periodically evaluate compliance with effluent limitations established in their permits and provide the
results to the permitting authority (DWQ). The DWQ permit writer should establish monitoring frequencies sufficient to characterize the effluent quality and detect noncompliance events,
considering the need for data and, as appropriate, the potential cost to the permittee. In addition to the guidelines below, to establish a monitoring frequency, the permit writer should
consider the following factors:
Federal Effluent Guidelines (https://www.epa.gov/eg)
Approved State or Federal Programs
Compliance history
Variability of various parameters
Treatment method used
Design capacity of the treatment facility
Location of discharge
Nature of the pollutants
Frequency of the discharge
Number of monthly samples used in developing effluent limitations
Tiered limitations
Current permit monitoring frequency
Cost of monitoring relative to permittee’s capability
Other factors the permit writer may deem relevant to the evaluation

Table 1. Suggested monitoring frequencies for different classes of pollutants.
Table 1 – Suggested Effluent Monitoring Frequency of Pollutant Classes
Parameter(1)
<0.5 MGD
0.5-1.0 MGD
1.0 - 5.0 MGD
5.0-15.0 MGD
>15.0 MGD
Flow
1/month
1/Week
Continuous
Continuous
Continuous
pH
1/month
1/Week
Daily
Continuous
Continuous
Conventional
1/month
1/Week
2/week
5-6/week
6-7/week
Nonconventional
1/month
1/Week
2/week
5-6/week
6-7/week
Toxics
1/year
2/year
4/year
6/year
1/month
Organic toxics
1/year
2/year
4/year
6/year
1/month
WET
4/year
4/year
4/year
4/year
1/month
Notes:
The frequency of the parameter's monitoring should be determined by the parameter’s water quality standard. If a parameter is expressed as a limit in a permit, then a minimum of monthly
sampling is recommended.
DWQ WET Guidance Document can be obtained by contacting the WET Program Coordinator.
Specific suggested frequencies for various pollutant parameters can be found in Appendix A. Appendix B contains approved test methods, sample type, and preservation protocol for each
pollutant parameter found in 40 CFR 136.3.
Appendix A – Monitoring Frequencies
Suggested Effluent Monitoring Frequency (1
Parameter
<0.5 MGD

0.5-1.0 MGD
1.0 - 5.0 MGD
5-15 MGD
>15 MGD
Conventional
Flow
1/month
1/Week
Continuous
Continuous
Continuous
pH
1/month
1/Week
Daily
Continuous
Continuous
Biochemical Oxygen Demand
1/month
1/Week
2/week
5-6/week
6-7/week
Carbonaceous Biochemical Oxygen Demand
1/month
1/Week
2/week
5-6/week
6-7/week
Total Suspended Solids
1/month
1/Week
2/week
5-6/week
6-7/week
Oil & Grease
1/month
1/month
1/month
1/month
1/month
E. coli
1/month
1/Week
2/week
5-6/week
6-7/week
Dissolved Oxygen
1/month
1/Week
2/week
5-6/week
6-7/week
Turbidity
1/month
1/Week
2/week
5-6/week
6-7/week
Temperature

1/month
1/Week
2/week
5-6/week
6-7/week
Total Dissolved Solids(2)
1/month
1/month
1/month
1/Week
5-7/week
Total Residual Chlorine
1/month
1/Week
2/week
5-6/week
6-7/week
Nonconventional
Total Ammonia (N)(3)
1/month
1/month
1/month
1/Week
3/week
Chemical Oxygen Demand
1/month
Weekly
2/week
5-6/week
6-7/week
Nitrate
1/month
1/month
1/month
1/month
2/month
Nitrate-nitrite(3)
1/month
1/month
1/month
1/month
2/month
Nitrite
1/month
1/month
1/month
1/month
2/month
Ortho-phosphorus(3)
1/month
1/month
1/month
1/month
2/month
Total Kjeldahl Nitrogen(3)
1/month
1/month
1/month
1/month
2/month

Total Organic Carbon
1/month
1/month
1/month
1/month
2/month
Total Phosphorus(3)
1/month
1/month
1/month
1/month
2/month
Toxics(4)
Arsenic, Total
None
None
4/year
4/year
6/year
Boron, Total
None
None
4/year
4/year
6/year
Cadmium, Total
None
None
4/year
4/year
6/year
Chromium, Total
None
None
4/year
4/year
6/year
Copper, Total
None
None
4/year
4/year
6/year
Cyanide, Total
None
None
4/year
4/year
6/year
Lead, Total
None
None
4/year
4/year
6/year
Mercury, Total
None
None
4/year
4/year

6/year
Nickel, Total
None
None
4/year
4/year
6/year
Selenium, Total
None
None
4/year
4/year
6/year
Silver, Total
None
None
4/year
4/year
6/year
Zinc, Total
None
None
4/year
4/year
6/year
Parameter
<0.5 MGD
0.5-1.0 MGD
1.0 - 5.0 MGD
5-15 MGD
>15 MGD
Organic Toxics
Organic Toxics
None
None
4/year
4/year
6/year
WET(5)(6)
Toxicity acute, freshwater organisms, LC50, percent effluent
4/year
4/year
4/year
4/year
1/month
Toxicity acute, estuarine and marine organism of the Atlantic Ocean and gulf of Mexico, LC, percent effluent
4/year
4/year
4/year
4/year
1/month
Toxicity chronic, freshwater organisms, NOEC or IC25, percent effluent
4/year
4/year
4/year
4/year
1/month
Toxicity chronic, estuarine and marine organisms of the Atlantic Ocean and Gulf of Mexico, NOEC or IC25, percent effluent
4/year
4/year

4/year
4/year
1/month
Notes:
This Appendix is intended as guidance, monitoring frequency may be altered based on factors identified in the “Guidance” section of this document.
The Total Dissolved Solids monitoring frequency listed in this table fulfills the monitoring guidance found in the 2023 Review Water Quality Standards for Salinity Colorado River System,
page B14.
Technology-based limits for controlling phosphorus pollution for all non-lagoon discharging systems found in UAC R317-1-3.3.E require monthly influent sampling for total phosphorus (as
P) and total Kjeldahl nitrogen (as N). Monthly effluent sampling for total phosphorus and orthophosphate (as P), ammonia, nitrate-nitrite, and total Kjeldahl nitrogen (as N). All monitoring
required by UAC R317-1-3.3.E shall be based on 24-hour composite samples by use of an automatic sampler or by combining a minimum of four grab samples collected at least two hours apart
within a 24-hour period.
Facilities with a flow of less than 1.0 MGD, toxics monitoring frequency will be evaluated based on the need to asses reasonable potential or if there are industrial users connected
to the Publicly Owned Treatment Works (POTW).
WET monitoring guidance recommends POTWs over 20 MGD or Industry over 10 MGD samples monthly. Quarterly testing is recommended for minor facilities. Minor testing frequency may be reduced,
however major facilities require a minimum monitoring frequency of quarterly.
If the results for ten consecutive tests indicate no toxicity, the permittee may request a reduction in acute toxicity testing by a reduction in monitoring frequency, alternating species,
or using only the most sensitive species. The Director may approve or deny the request. If the request is approved, the test procedures are to be the same as specified above for the
test species. Under no circumstances shall monitoring for WET at major facilities be reduced less than quarterly. Minor facilities may be less than quarterly at the discretion of the
Director.
Appendix B – Approved Test Methods, Sample Type, and Preservation Protocol
Approved Test Methods(1)
Preservation Protocol
Parameter
Sample Type(2)
EPA
SM
AOAC, ATSM, USGS
Other
Hold Time
Preservation
Container(3)
pH
g
150.2 (Dec. 1982)
4500-H+ B-2011
D1293-99(A or B)
973.41, I-1586-85, I-2587-85
Analyze within 15 minutes.
None required
P, FP, G
Biochemical Oxygen Demand
g,c

5210 B-2016

973.44, p. 17, I-1578-78
48 hrs
Cool, ≤6 °C
P, FP, G
Carbonaceous Biochemical Oxygen Demand
g,c

5210 B-2016

48 hrs
Cool, ≤6 °C
P, FP, G
Total Suspended Solids
g,c

2540 D-2015
D5907-13
I-3765-85
7 days
Cool, ≤6 °C
P, FP, G
Oil & Grease
g
1664 A and B
5520 B-2011, 5520 F-2011

28 days
Cool to ≤6 °C, HCl or H2SO4 to pH <2
G
E.coli
g
1603 21
9221 B2014/9221 F-2014 12 14 33, 9223 B-2016 12, 9222 B-2015/9222 I-2015 31
991.15 10
Colilert 13 18, Colilert-18 13 17 18, m-ColiBlue24.19
8 hrs
Cool, <10 °C, 0.008% Na2S2O3 5
PA, G
Dissolved Oxygen
g

4500-O (B-F)-2016, 4500-O G-2016, 4500-O H-2016
D888-12(A)(B)(C)
973.45B, I-1575-75, I-1576-78
Analyze within 15 minutes.
None required
G, Bottle and top
Turbidity
g,c
180.1 REV 2.0 (1993)
2130 B-2011
D1889-00
I-3860-85
48 hrs
Cool, ≤6 °C
P, FP, G
Temperature
g

2550 B-2010

Analyze within 15 minutes.
None required
P, FP, G
Total Dissolved Solids
g,c

2540 C-2015

7 days
Cool, ≤6 °C

P, FP, G
Residual Chlorine
g

4500-CL D,E,B,C,F,G-2011
D1253-14

Analyze within 15 minutes.
None required
P, G
Non-conventional Pollutants
Ammonia (N)
g,c
350.1, Rev 2.0 (1993)
4500-NH3 B-2011, 4500-NH3 C-2011, 45000-NH3 D-2011 or E-2011, 4500 NH3 F-2011, 4500 NH3 G-2011, 4500-NH3 H-2011
D1426-15(A),- D1426-15 (B), D6919-17
973.49, I-3520-85, I-4523-85, I-2522-90, Timberline Ammonia-001, FIAlab100
28 days
Cool, ≤6 °C, H2SO4 to pH <2
P, FP, G
Chemical Oxygen Demand
g,c
410.3 (Rev.1978), 410.4 Rev 2.0 (1993)
5220 B-2011 or C-2011, 5220 D-2011
D1252-06(12)(A), D1252-06(12)(B)
973.46, p.17, I-3560-85, 13 14 83, I-3561-85
28 days
Cool, ≤6 °C, H2SO4 to pH <2
P, FP, G
Nitrate
g,c
300.0 Rev 2.1, 300.1 Rev 1.0, 4140 B-2011 352.1
4110 B or C-2011, D6508-15, 4500-NO3-D
D4327-17, D6508 Rev2
993.30, 973.50, 419D p.28, Hach 10206
48 hrs
Cool, ≤6 °C
P, FP, G
Nitrate-nitrite
g,c
353.2 Rev 2.0, 900.0 Rev 2.1, 300.1 Rev 1.0
l4500-NO3-E,F,I, H,J, 4110 B,C-2011
D3867-16(B)(A), D4327-17, D6508-15, D7781-14
I-2545-90, 993.30, D6508 Rev2, I-254-11, I-2548-11, N07-0003, Hach 10206
28 days
Cool, ≤6 °C, H2SO4 to pH <2
P, FP, G
Nitrite
g,c
353.2 Rev 2.0, 300.0 Rev 2.1, 300.1 Rev1.0
4500-NO2-B,F,I,E,J, 4110 B,C-2011, 4140 B-2011
D3867-16(A)(B), D4327-17, D6508-15, D7781-14
I-4540-85, I-2540-90, I454-85, 993.30, D6508 Rev 2, I-2547-11, I-2548-11, N07-0003
48 hrs
Cool, ≤6 °C
P, FP, G
Ortho-phosphorus
g,c
365.1 Rev 2.0 (1993), 365.3, 300.0 Rev 2.1 and 300.1 Rev 1.0
4500-P E or G-2011, 4110 B or C-2011, 4140 B-2011

D515-88(A), D4327-17, D6508-15
973.56, I-4601-85, I-2601-90
Filter within 15 minutes; Analyze within 48 hours
Cool, ≤6 °C
P, FP, G
Total Kjeldahl Nitrogen
g,c
350.1 Rev 2.0, 351.1 Rev 1978, 351.2 Rev 2.0 1993
4500-Norg B-2011 or C-2011, 4500 NH3 B-2011, 4500 NH3 C-2011, 4500-NH3 D-2011 or E-2011, 4500-NH3 G-2011, 4500-NH3 H-2011, 4500-NH3 F-2011, 4500-Norg D-2011
D3590-17(A), D1426-15(A), D1426-15(B), D3590-17(B)
I-4515-91, 973.48, Timberline Ammonia-001, FIAlab100, I-4551-78, I-4515-91, Hach 10242, NCASI TNTP W10900
28 days
Cool, ≤6 °C, H2SO4 to pH <2
P, FP, G
Total Organic Carbon
g,c

5310-B,C,D
D7573-09(17), D4839-03(17)
973.47 p.14
28 days
Cool to ≤6 °C, HCl, H2SO4, or H3PO4 to pH <2
P, FP, G
Total Phosphorus
g,c
365.3, 365.1, 200.7, 365.4
4500-P B(5) 2011, 4500-P E-2011, 4500-P (F-H)-2011< 3120 B-2011
D515-88(A), D515-88(B)
973.55, 973.56, I-4600-85, I4471-97, I-4610-91, NCASI TNTP W10900
28 days
Cool, ≤6 °C, H2SO4 to pH <2
P, FP, G
Toxic Pollutants
Arsenic, Total
g,c
206.5, 200.9 rev 2.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3111 B-2011, 3111 C-2011, 3113 B-2010, 3120 B-2011, 3125 B-2011, 3500-As-B-2011
D2972-15(B), D2972-15(c), D1976-12, D5673-16, D2972-15(A)
I-3062-85, I-4063-98, 993.14, I-4020-05, I-3060-85
6 months
HNO3 to pH <2
P, FP, G
Boron, Total
g,c
200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3120 B-2011, 3125 B-2011
D1976-12, D5673-16, D4190-15
973.44, I-1578-78, I-3112-85, I-4471-97, 993.14, S7
6 months
HNO3 to pH <2
P, FP, or Quartz
Cadmium, Total
g,c
200.9 rev 2.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3120 B-2011, 3125 B-2011, 3500-Cd-D-2011
D3557-17 (A or B), D3557-17 (D), D1976-12, D5673-16, D4190-15, D3557-17 (c)
974.27, I-3135-85, I3136-85, I-1438-89, I1472-85, I-4471-97, 993.14, I-4472-97
6 months
HNO3 to pH <2
P, FP, G

Chromium, Total
g,c
200.9 rev 2.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3111 B-2011, 3111 C-2011, 3113 B-2010, 3120 B-2011, 3125 B-2011, 3500-Cr-B-2011
D1687-179B), D1687-17(c), D1976-12, D5673-16, D4190-15
974.27, I-3236-85, I-3233-93, 993.14, I-4020-05, I-4472-97
6 months
HNO3 to pH <2
P, FP, G
Copper, Total
g,c
200.9 rev 2.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3111 B-2011, 3111 C-2011, 3113 B-2010, 3120 B-2011, 3125 B-2011, 3500-Cu-B-2011, 3500-Cu-C
D01688-17(A or B), D1688-17(c), D1976-12, D5673-16, D4190-15
924.27, I-3270-85, I-3271-85, I-4272-89, I-4471-97, 993.14, I-4020-05, I-4472-97
6 months
HNO3 to pH <2
P, FP, G
Cyanide, Total
g,c
335.4 rev 1.0,
4500-CN-B and C, 4500-CN-D, 4500-CN-E, 4500-CN-N, 4500-CN-F
D7511-12(17), D2036-09(15)(A), D7284-13(17), D2036-09(15)(A), D7284-13(17), D2036-09(15)(A)
Kelada-01, 10-204-00-1-X, I-3300-85, 10-204-00-1-X, I-4302-85
14 days
Cool, ≤6 °C, NaOH to pH >10, reducing agent of oxidizer present
P, FP, G
Lead, Total
g,c
200.9 rev 2.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3111 B-2011, 3111 C-2011, 3113 B-2010, 3120 B-2011, 3125 B-2011, 3500-Pb-B-2011
D3559-15(A or B), D3559-15(D), D1976-12, D5673-16, D4190-15, D3559-15(c)
974.27, I-3399-85, I-4403-89, I-4471-97, 993.14, I-4472-97
6 months
HNO3 to pH <2
P, FP, G
Mercury, Total
g,c
245.1 Rev 3.0, 245.2, 245.7 rev 2.0, 1631E*
3112 B-2011
D3223-17
977.22, I-3462-85, I-4464-01
28 days
HNO3 to pH <2
P, FP, G
Nickel, Total
g,c
200.9 rev 2.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3111 B-2011, 3111 C-2011, 3113 B-2010, 3120 B-2011, 3125 B-2011
D1886-14(A or B), D1886-14©, D1976-12, D5673-16, D4190-15
I-3499-85, I-4503-89, I4471-97, 993.14, I-4020-05, I-4472-97
6 months
HNO3 to pH <2
P, FP, G
Selenium, Total
g,c
200.9 rev 2.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3113 B-2010, 3120 B-2011, 3125 B-2011, 3114 B-2011, 3114 C-2011
D3859-15(B), D1976-12, D5673-16, D3859-15(A)
I-4668-98, 993.14, I-4020-05, I-4472-97, I-3667-85

6 months
HNO3 to pH <2
P, FP, G
Silver, Total
g,c
200.9 rev 2.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3111 B-2011, 3111 C-2011, 3113 B-2010, 3120 B-2011, 3125 B-2011
D1976-12, D5673-16
974.27, I-3720-85, I-4724-89, I-4471-97, 993.14, I-4472-97
6 months
HNO3 to pH <2
P, FP, G
Zinc, Total
g,c
289.2, 200.5 rev 4.2, 200.7 rev 4.4, 200.8 rev 5.4
3111 B-2011, 3111 C-2011, 3120 B-2011, 3125 B-2011, 3500Zn B-2011
D1691-17(A or B), D1976-12, D5673-16, D4190-15
974.27, I-3900-85, I-4471-97, 993.14, I-4020-05, I-4472-97
6 months
HNO3 to pH <2
P, FP, G
Organic Toxics
Organic Toxics
Varies based on parameter
Varies based on parameter
Varies based on parameter
Varies based on parameter
Varies based on parameter
Varies based on parameter
Varies based on parameter
Varies based on parameter
WET 
Toxicity acute, freshwater organisms, LC50, percent effluent
c
2002.0 25 - Water flea, Cladoceran, Ceriodaphnia dubia; 2021.0 25-Water fleas, cladocerans, daphnia pulex and daphnia magna; 2000.0 25-Fish, fathead minnow, pimephales promelas, and
bannerfin shiner, cyprinella leedsi; 2019.025=-fish rainbow trout, oncorhynchus mykiss, andtrout, salvelinus fontinalis

36 hrs
Cool, ≤6 °C 
P, FP, G
Toxicity acute, estuarine and marine organism of the atlantic ocean and gulf of mexico, LC, percent effluent
c
2007.0 25-Mysid, mysidopsis bahia; 2004.0 25-fush, sheepshead minnow, cyprinodon variegatus; 2006.0 25-fish silverside, menidia beryllina, menidia menidia, and menidia peninsulae

36 hrs
Cool, ≤6 °C
P, FP, G
Toxicity chronic, fresh water organisms, NOEC or IC25, percent effluent
c
1000.0 26-fish, fathead minno, pimephales promelas, larval survial and growth; 1001.0 26-fish fathead minnow, pimephales promelas, embryo=-larval survial and teratogenicity; 1002.0 26-water
flea, cladoceran, ceriodaphnia dubia, survial and reproduction; 1003.0 26-green alga, selenastrum capricornutum, growth

36 hrs
Cool, ≤6 °C 

P, FP, G
Toxicity chronic, estuarine and marine organisms of the atlantic ocean and gluf of mexico, NOEC or IC25, percent effluent
c
1004.0 27-fish, sheepshead minnow, cyprinodon variegatus, larval survival and growth; 1005.0 27-fIsh, sheepshead minnow, cyprinodon variegatus, embryo-lavral survival and teratogenicity;
1006.0 27-fish, inland silverside, menidia beryllina, larval survival and growth; 1007.0 27-mysid, mysidopsis bahia, survival, growth, and fecundity; 1008.0 27-sea urchin, arbacia punctulata,
fertilization

36 hrs
Cool, ≤6 °C 
P, FP, G
Notes
This list of approved test methods is not exhaustive. Approved test methods come from tables found 40 CFR 136.3.
Samples and measurements taken for the purpose of monitoring shall be representative of the monitored activity.
g – grab sample
c – composite sample
Container Type
P – polyethylene
FP – fluoropolymer
G – glass
PA - plastic made of sterilized material