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The healthiest and least healthy streams

1,229 of 1,233 Ohio ZIP codes have a figure; the median one has 81% of the land impaired.

Open this topic on the map Stream health by ZIP code

Ohio judges its streams watershed by watershed. Every two years Ohio EPA reports which of its 1,545 assessment units support aquatic life, the standard that asks whether fish and insects can live there, and the answers follow the land: forested headwaters with intact banks tend to pass, while heavily farmed, mined or hard-surfaced watersheds often do not. Nearly every watershed in the state fails the separate recreation standard on bacteria, so aquatic life is the better yardstick.

This lists both ends by the share of each ZIP code's land that drains to streams Ohio EPA assessed as not supporting aquatic life in its 2024 integrated report: the 25 ZIP codes with the least of it, and, separately, the 25 with the most. Many ZIP codes drain to no impaired stream at all and share a value of zero; those are listed by ZIP code.

Across the state

One dot per ZIP code, colored the way the map colors this topic; larger dots are more populous ZIP codes.

Streams support aquatic life throughout (105) Under a quarter of the land drains to impaired streams (105) A quarter to a half (161) Half to three quarters (196) Three quarters or more (662) No data (4)

The 25 healthiest

Least impaired first; every ZIP code links to its own page.

  1. 43005 · Jackson Township and BladensburgKnox County0% of the land impaired
  2. 43010 · CatawbaClark County0% of the land impaired
  3. 43018 · Etna Township and EtnaLicking County0% of the land impaired
  4. 43030 · Licking Township and JacksontownLicking County0% of the land impaired
  5. 43033 · KirkersvilleLicking County0% of the land impaired
  6. 43037 · Clay Township and MartinsburgKnox County0% of the land impaired
  7. 43071 · Eden Township and Saint LouisvilleLicking County0% of the land impaired
  8. 43077 · Unionville CenterUnion County0% of the land impaired
  9. 43101 · AdelphiRoss County0% of the land impaired
  10. 43116 · Commercial PointPickaway County0% of the land impaired
  11. 43117 · Darby Township and DerbyPickaway County0% of the land impaired
  12. 43126 · HarrisburgFranklin County0% of the land impaired
  13. 43325 · Washington Township and IberiaMorrow County0% of the land impaired
  14. 43433 · Portage Township and GypsumOttawa County0% of the land impaired
  15. 43437 · Jerry CityWood County0% of the land impaired
  16. 43440 · Danbury Township and Lakeside MarbleheadOttawa County0% of the land impaired
  17. 43505 · BlakesleeWilliams County0% of the land impaired
  18. 43510 · Washington Township and ColtonHenry County0% of the land impaired
  19. 43522 · Providence Township and Grand RapidsWood County0% of the land impaired
  20. 43523 · Monroe Township and GreltonHenry County0% of the land impaired
  21. 43525 · HaskinsWood County0% of the land impaired
  22. 43530 · Richland Township and JewellDefiance County0% of the land impaired
  23. 43534 · Damascus Township and Mc ClureHenry County0% of the land impaired
  24. 43541 · Milton CenterWood County0% of the land impaired
  25. 43547 · Providence Township and NeapolisLucas County0% of the land impaired

96 ZIP codes share the last value listed (0% of the land impaired); the 25 shown come first by ZIP code.

The 25 least healthy

Most impaired first; every ZIP code links to its own page.

  1. 43002 · Columbus and AmlinFranklin County100% of the land impaired
  2. 43004 · Columbus and BlacklickFranklin County100% of the land impaired
  3. 43007 · Taylor Township and BroadwayUnion County100% of the land impaired
  4. 43027 · Burlington Township and HomerLicking County100% of the land impaired
  5. 43032 · Brown Township and KilbourneDelaware County100% of the land impaired
  6. 43036 · Magnetic SpringsUnion County100% of the land impaired
  7. 43047 · Wayne Township and MingoChampaign County100% of the land impaired
  8. 43060 · North LewisburgChampaign County100% of the land impaired
  9. 43068 · ReynoldsburgFranklin County100% of the land impaired
  10. 43070 · Adams Township and RosewoodChampaign County100% of the land impaired
  11. 43107 · Rushcreek Township and BremenFairfield County100% of the land impaired
  12. 43109 · BriceFranklin County100% of the land impaired
  13. 43111 · Ward Township and Carbon HillHocking County100% of the land impaired
  14. 43127 · Green Township and HaydenvilleHocking County100% of the land impaired
  15. 43142 · MilledgevilleFayette County100% of the land impaired
  16. 43144 · Murray CityHocking County100% of the land impaired
  17. 43151 · Midway and SedaliaMadison County100% of the land impaired
  18. 43156 · TarltonPickaway County100% of the land impaired
  19. 43157 · ThurstonFairfield County100% of the land impaired
  20. 43158 · Starr Township and Union FurnaceHocking County100% of the land impaired
  21. 43201 · ColumbusFranklin County100% of the land impaired
  22. 43202 · ColumbusFranklin County100% of the land impaired
  23. 43203 · ColumbusFranklin County100% of the land impaired
  24. 43204 · ColumbusFranklin County100% of the land impaired
  25. 43205 · ColumbusFranklin County100% of the land impaired

356 ZIP codes share the last value listed (100% of the land impaired); the 25 shown come first by ZIP code.

How this was measured

Ohio EPA's 2024 Integrated Report as published in EPA's ATTAINS database: Ohio judges its rivers and streams watershed by watershed (1,545 assessment units) against the uses the Clean Water Act protects. The map shows the share of each ZIP's land in watersheds whose streams fail the aquatic-life standard, the one that says whether fish and insects can live there; the card adds recreation (bacteria), fish consumption and, where a stream is a drinking-water source, that use, plus the listed causes. Nearly every Ohio watershed fails the recreation standard because of bacteria, so aquatic life is the better yardstick. The card also carries Ohio EPA's fish consumption advisories for the rivers and lakes that touch the ZIP: which species to limit to a meal a month or six a year, and whether PCBs or mercury are the reason. The card also carries the USGS estimate of farm pesticide use in the county for 2018, with atrazine, the herbicide most often found in Ohio tap water, called out. Below that sits the county's 2022 Census of Agriculture profile: farms, acres, cropland share, livestock and crop acreage. The nearest Ohio EPA assessment station gives the actual fish, bug and habitat scores behind those verdicts. The nearest station of Ohio EPA's large river PFAS survey gives PFAS in the water and in fish. Ohio EPA's use designations give the miles of exceptional, warmwater, coldwater and modified streams in the ZIP and the nearest superior or outstanding water. Federal critical habitat for endangered mussels and fish is flagged where it crosses the ZIP. Reaches proposed for new antidegradation protection in the 2026 rules are noted.

The figure is the share of each ZIP code's land that drains to streams Ohio EPA assessed as not supporting aquatic life; many ZIP codes share a value of zero, and those listed come first by ZIP code.

1,229 of 1,233 ZIP codes have a figure; ZIP codes without one are left off the list, not counted as zero. Ties are broken by ZIP code.

Every ZIP code's own page carries the full detail behind its figure, and the Stream health topic page ranks the whole state.

Sources

EPA ATTAINS, Ohio 2024 Integrated Report assessment units (1,545 watershed polygons) overlaid on ZCTAs in Albers equal-area with the Lake Erie units clipped out: share of land in units not supporting aquatic life, recreation, fish consumption and drinking-water uses, with causes; Ohio EPA sport fish consumption advisories (SurfaceWater/DSW_FA_Consumption_SPS_Public) for water bodies touching the ZIP; USGS preliminary county agricultural pesticide use estimates for 2018 (high estimate) for the county; USDA 2022 Census of Agriculture county totals (NASS Quick Stats bulk file); Ohio EPA aquatic life use assessments (Monitoring_EA3 layer 1: IBI, ICI, QHEI and attainment by station); Ohio EPA aquatic life use designations and antidegradation tiers (SurfaceWater/Beneficial_Uses); U.S. Fish and Wildlife Service final critical habitat polygons intersecting the ZIP; Ohio EPA proposed 2026 antidegradation tiers (SurfaceWater/Antideg_Proposed_2026).

EPA ATTAINS · Ohio integrated report · Ohio sport fish advisory · Ohio EPA advisory map

The figures behind this page are open data: the open JSON, CC BY 4.0 for the compilation. Report a correction.

Cite this page as:

Cracked Buckeye (Open Shower Co), "The healthiest and least healthy streams", https://crackedbuckeye.com/stories/stream-health/, built 2026-09-16, accessed [date].

One figure from it:

Cracked Buckeye (Open Shower Co), "The healthiest and least healthy streams", https://crackedbuckeye.com/stories/stream-health/, built 2026-09-16, accessed [date]; Stream health from EPA ATTAINS.

How to cite · Report a correction · Built 2026-09-16