State water-quality picture · #36 by reported lake-type waterbodies
Utah lakes and reservoirs
Every figure on this page is computed from the assessment decisions Utah reported to the U.S. Environmental Protection Agency under Clean Water Act sections 303(d) and 305(b) (reporting cycles 2014–2026), plus daily water-level observations from the U.S. Geological Survey.
- 143
- Reported waterbodies
- 77
- Not supporting a use
- Not reported
- Fish use assessments
- 1
- Gauged lake
Utah in one line
143 lake-type waterbodies in Utah are reported to EPA ATTAINS across reporting cycles 2014–2026: 77 assessed as not supporting at least one designated use, 60 fully supporting, and 6 without a definitive overall verdict. The most-listed impairment cause is pH, on 38 waterbodies.
- 143
- reported waterbodies
- 77
- not supporting a use
- 60
- fully supporting
- 57%
- of definitive verdicts impaired
An unassessed waterbody is neither confirmed clean nor confirmed impaired; states assess on multi-year cycles. 3 of those 60 fully supporting verdicts (5%) rest on designated uses this site does not report (irrigation, navigation and industrial water supply), with Utah recording no verdict on fish consumption, recreation, aquatic life and drinking water. They are counted above because the state filed them, and excluded from the impaired share below because that figure compares states.
Utah's smaller reported lake-type inventory
At 143 units, Utah is in the lowest third of state lake-type registers. The charts below describe that compact filing set, not a national-scale inventory.
Data updated 2026-08-17
According to the U.S. Environmental Protection Agency's ATTAINS program, Utah reported 143 lake-type waterbodies in Utah in the August 2026 extract. See our methodology for filer attribution and multi-year reporting cycles.
Overall-status split on Utah's compact register
Every reported lake-type unit in this smaller Utah filing set falls into exactly one overall-status bucket. The bar partitions 143 units; cause and gauge panels below stay separate.
Most-listed impairment causes in Utah
Waterbodies carrying each listed cause, most first
- pH
pH
38 waterbodies
- Phosphorus, Total
Phosphorus, Total
35 waterbodies
- Dissolved Oxygen
Dissolved Oxygen
33 waterbodies
- Temperature
Temperature
31 waterbodies
- Harmful Algal Blooms
Harmful Algal Blooms
23 waterbodies
What this shows pH is the most-listed impairment cause in Utah, on 38 of the lake-type waterbodies reported there.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
Utah: 57% of ruled verdicts are not-supporting, against a national share of 53%, 1.1× the national rate.
Reporting practice
Nearly all of Utah's inventory carries a definitive verdict
Each reporting authority decides how much of the water it files to EPA it actually assesses in a cycle. That decision sets the denominator behind every count on this page.
Utah holds the 36th-largest reported lake-type inventory in the country, 143 assessment units, carrying a definitive verdict on 93.7% of it. The counts above describe the 134 units carrying a verdict, not all 143 reported.
The states reporting at the nearest rates are Georgia (95.2%) and Kentucky (91.5%).
Assessing more of an inventory is a reporting choice, set by cycle length, monitoring budget and how finely a state splits its waters into units. It is not a measure of water quality, and it is why a raw count from one state does not sit beside a raw count from another. How assessment coverage varies.
Utah against every comparable state
Share of reported lake-type waterbodies carrying a definitive verdict
93.7% 10th of 47 higher than 37 of 47 states
the 47 comparable states, by definitive-verdict share
Each bar is a band; taller bars hold more states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA ATTAINS · Reporting cycles 1987–2026
Each bar counts states whose definitive-verdict share falls in that 10-point band. The 47 states shown are those reporting at least 25 lake-type units; a share off a smaller inventory is precision the data does not have.
By size
Largest assessed lakes in Utah
By assessed acreage as reported in ATTAINS. Acreage is the assessed unit's size, which can differ from a lake's full surface area.
| # | Waterbody | Assessed acres |
|---|---|---|
| 1 | Gilbert Bay Fully Supporting | 559,424 |
| 2 | Gunnison Bay Not Assessed | 384,588 |
| 3 | Lake Powell Fully Supporting | 149,885 |
| 4 | Utah Lake other than Provo Bay Not Supporting | 87,984 |
| 5 | Farmington Bay Not Assessed | 77,243 |
| 6 | Bear River Bay Not Assessed | 71,681 |
| 7 | Bear Lake Fully Supporting | 35,414 |
| 8 | Strawberry Reservoir Not Supporting | 15,614 |
| 9 | Flaming Gorge Reservoir Not Supporting | 12,525 |
| 10 | Willard Bay Reservoir Not Supporting | 10,109 |
| 11 | Sevier Bridge Reservoir (Yuba Lake) Not Supporting | 8,978 |
| 12 | Provo Bay portion of Utah Lake Not Supporting | 3,612 |
By cause count
Most-listed waterbodies in Utah
Waterbodies carrying the most listed impairment causes among the lake-type units reported by Utah.
| # | Waterbody | Listed causes |
|---|---|---|
| 1 | Big East Lake Not Supporting | 6 |
| 1 | Provo Bay portion of Utah Lake Not Supporting | 6 |
| 1 | Utah Lake other than Provo Bay Not Supporting | 6 |
| 4 | Calder Reservoir Not Supporting | 5 |
| 4 | Mantua Reservoir Not Supporting | 5 |
| 4 | Matt Warner Reservoir Not Supporting | 5 |
| 4 | Newcastle Reservoir Not Supporting | 5 |
| 4 | Pineview Reservoir Not Supporting | 5 |
| 4 | Scofield Reservoir Not Supporting | 5 |
| 10 | Baker Dam Reservoir Not Supporting | 4 |
9 of the 10 rows in this table tie on the ranked value: 3 at 6 (rank 1), 6 at 5 (rank 4). Tied rows share a rank and are listed in no meaningful order; where a tie reaches the top the medal is shared, because nothing separates those rows.
Gauge network
Lakes with a daily level record in Utah
Lakes with a linked USGS gauge and a daily water-level record. Readings are daily-batch snapshots, not real-time.
States with similar inventory scale or impairment load
Two EPA ATTAINS peer sets outside Utah. The reporting-practice chart above stays on definitive-verdict share; these neighborhoods are cross-state nearest neighbors on register size and not-supporting counts.
Comparable register size
Nearest states by lake-type units on the register (143 here).
Comparable not-supporting counts
Nearest states by units assessed not supporting a use (77 here). Inventory peers above are omitted.
- Colorado · 89 not supporting · 12 off
- North Carolina · 90 not supporting · 13 off
- Louisiana · 64 not supporting · 13 off
- North Dakota · 52 not supporting · 25 off
Peers are nearest-neighbor matches on EPA ATTAINS register size and not-supporting counts among states with at least 25 reported units. Impairment peers skip states already listed in the inventory column so the two link sets stay distinct.
Using this state picture
- Comparisons across states hold on shares, not counts: 93.7% of the inventory reported from Utah carries a definitive verdict, 10th of 47 comparable states. National rankings
- Fish-consumption verdicts here are assessment decisions. Species-level meal advice comes from the state fish-advisory program. Consumption guide
- Browse every named Utah waterbody with a populated record. Browse waterbodies
PlainLakes renders state assessment decisions and federal gauge observations without modification.
Figures on this page are computed from the assessment decisions Utah reported to EPA's ATTAINS system and from USGS National Water Information System daily values, no number is typed in by an editor. State counts aggregate every lake-type assessment unit reported by Utah, including unnamed units that never receive their own page. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-08-17. Primary sources: EPA ATTAINS and USGS National Water Information System.