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Water quality

Cleanest water in Slovakia

Fishing districts with no failed standard
31
Sites on watercourses with no failed standard
140
Groundwater stations without an exceedance
138
Groundwater stations within the standard by measurements
363

Where the water is cleanest

The opposite of the pollution page: what came out without a failed standard

  • Surface water, 2025SHMÚ state monitoring sites on watercourses and reservoirs
    • 69sites met all standards
    • 91fails the standard only in indicators outside the score (mainly PAHs, salts, minerals)
    • 203fails the standard for oxygen, nutrients, metals or harmful substances
  • Groundwater, 2025SHMÚ monitoring stations
    • 298stations without an exceedance of the standard
    • 289standard exceeded for other substances (often natural: iron, manganese, sulfates)
    • 171substances from human activity (nitrates, pesticides, PFAS, solvents)
  • Treatment plants near the fishing districtstreatment plants within 2 km of the fishing district; problem = fails EU requirements or is overloaded above 100 %
    • 230treatment plants with no fault found
    • 35treatment plants with a problem (7 fail EU requirements, 29 overloaded)
  • Fishing districtsall assessed fishing districts
    • 31fishing districts meet all the clean-water conditions
    • 1 365others (a condition not met or data missing)

The cleanest water is where state monitoring did not catch it exceeding any standard. Of 363 sites in the SHMÚ yearbook for 2025, 69 (19 %) met all indicators. The remaining sites fail the standard in at least one indicator, mostly PAHs from combustion and minerals, less often nutrients and oxygen.

How a fishing district gets onto the list and what the list does not say

A fishing district appears in the list if three conditions are met: the nearest SHMÚ site on the same watercourse met the standards in all the years in the yearbook, there are not half or more groundwater stations with substances from human activity nearby, and the treatment plant within 2 km of the district is neither overloaded nor failing EU requirements. If we have groundwater measurements for the area around the fishing district, those must also be within the standard: nitrates below 25 mg/l, no metals, pesticides, PFAS or solvents above the standard, and no ammonium, nitrites, iron or chlorides above the limit. There are 31 such fishing districts.

What the list does not say: the surface water yearbook lists only the indicators that failed the standard, not the measured values. “Clean” here therefore means “nothing above the standard”, not “the best measured figures”. For groundwater we have measured values, and for districts where we have measured values from the European register, we give oxygen, nitrates and phosphorus directly at the fishing district. The location of a SHMÚ site is often only approximate, so there is a note next to them.

Map of fishing districts by cleanliness

Green line: no standard was failed at the nearest SHMÚ site

Detailed filtersregion, district, riverbed, depth, shading, satellites, water chemistry and pollution, fish, geology

1445fishing districts
Pick a category to narrow the selection. Next to each option you can see how many fishing districts remain.
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A green line means that at the nearest SHMÚ site no standard was failed in the 2025 yearbook. The darker towards red the line, the more indicators fail. Grey fishing districts have no site with the same watercourse name nearby. You can also switch the colour to groundwater and treatment plants.

Fishing districts with the cleanest water

No failed standard, no problem with groundwater or a treatment plant nearby

  • Teplička (Trenčín)SHMÚ site Trenčianska Teplá (right at the fishing district) · Trenčín Region · groundwater nearby within the standard (nitrates typically 17.0 mg/l)no unmet standard
  • Tovarský potokSHMÚ site Červený Kameň, nad (right at the fishing district) · Trenčín Region · groundwater nearby within the standard (nitrates typically 11.8 mg/l)no unmet standard
  • TisovníkSHMÚ site Vieska (1.6 km) · Banská Bystrica Regionno unmet standard
  • Čierny Váh č. 2SHMÚ site Ipoltica, osada Čierny Váh, nad (1.6 km) · Žilina Region · groundwater nearby within the standard (nitrates typically 3.3 mg/l)no unmet standard
  • Dunaj č. 3SHMÚ site ČOV Slovnaft, pod (8.5 km) · Trnava Region · groundwater nearby within the standard (nitrates typically 0.5 mg/l)no unmet standard
  • Biely potok (Martin)SHMÚ site Sučany, nad (Uhlisko) (right at the fishing district) · Žilina Region · groundwater nearby within the standard (nitrates typically 10.5 mg/l)the location of the site is only approximateno unmet standard
  • Bitarovský potokSHMÚ site Bánová, pred (right at the fishing district) · Žilina Region · groundwater nearby within the standard (nitrates typically 22.9 mg/l)the location of the site is only approximateno unmet standard
  • Hornád č. 2cSHMÚ site ÚKČ Košice, pod (right at the fishing district) · Košice Region · groundwater nearby within the standard (nitrates typically 4.5 mg/l)the location of the site is only approximateno unmet standard
  • Levočský potok č. 1SHMÚ site Levočský potok, ústie (right at the fishing district) · Košice Region · groundwater nearby within the standard (nitrates typically 8.0 mg/l)the location of the site is only approximateno unmet standard
  • MútňankaSHMÚ site Mútne, nad (right at the fishing district) · Žilina Regionthe location of the site is only approximateno unmet standard
  • Orava č. 1aSHMÚ site Orava, vyústenie OV z MAHLE Components a WWT Dolný Kubín, pod (right at the fishing district) · Žilina Region · groundwater nearby within the standard (nitrates typically 22.3 mg/l)the location of the site is only approximateno unmet standard
  • Rajčanka č. 1SHMÚ site Kľače-pod objektami Farmy Bárdy (right at the fishing district) · Žilina Region · groundwater nearby within the standard (nitrates typically 22.9 mg/l)the location of the site is only approximateno unmet standard
  • Stupavský potok č. 2SHMÚ site Stupavský potok, nad ČOV Borinka (right at the fishing district) · Bratislava Region · groundwater nearby within the standard (nitrates typically 10.9 mg/l)the location of the site is only approximateno unmet standard
  • SúčankaSHMÚ site Hrabovka, pri (right at the fishing district) · Trenčín Region · groundwater nearby within the standard (nitrates typically 21.6 mg/l)the location of the site is only approximateno unmet standard
  • Varínka č. 1bSHMÚ site Terchová, nad (Stará dolina) (right at the fishing district) · Žilina Region · groundwater nearby within the standard (nitrates typically 10.5 mg/l)the location of the site is only approximateno unmet standard
  • Jakubianka č. 2SHMÚ site Stará Ľubovňa (0.1 km) · Prešov Region · groundwater nearby within the standard (nitrates typically 4.1 mg/l)the location of the site is only approximateno unmet standard
  • Hornád č. 2bSHMÚ site ÚKČ Košice, pod (0.3 km) · Košice Region · groundwater nearby within the standard (nitrates typically 9.1 mg/l)the location of the site is only approximateno unmet standard
  • Stupavský potok č. 1SHMÚ site Stupavský potok, nad ČOV Borinka (0.9 km) · Bratislava Region · groundwater nearby within the standard (nitrates typically 11.7 mg/l)Measured: dissolved oxygen 11.5 mg/l, nitrates 2.3 mg N/l, phosphorus (phosphates) 0.03 mg P/lthe location of the site is only approximateno unmet standard
  • Hornád č. 2aSHMÚ site ÚKČ Košice, pod (2.9 km) · Košice Region · groundwater nearby within the standard (nitrates typically 9.1 mg/l)the location of the site is only approximateno unmet standard
  • Hnilec č. 4SHMÚ site ŽST Vernár, nad (3.0 km) · Košice Region · groundwater nearby within the standard (nitrates typically 6.4 mg/l)the location of the site is only approximateno unmet standard
  • Varínka č. 1aSHMÚ site Terchová, nad (Stará dolina) (3.8 km) · Žilina Region · groundwater nearby within the standard (nitrates typically 10.5 mg/l)the location of the site is only approximateno unmet standard
  • Hron č. 6aSHMÚ site Tekovská Breznica (4.2 km) · Banská Bystrica Region · groundwater nearby within the standard (nitrates typically 21.5 mg/l)the location of the site is only approximateno unmet standard
  • Levočský potok č. 2SHMÚ site Levočský potok, ústie (5.0 km) · Prešov Region · groundwater nearby within the standard (nitrates typically 2.8 mg/l)the location of the site is only approximateno unmet standard
  • Okna č. 2SHMÚ site Senné, nad (8.6 km) · Košice Region · groundwater nearby within the standard (nitrates typically 5.7 mg/l)Measured: dissolved oxygen 10.9 mg/l, nitrates 1.0 mg N/l, phosphorus (phosphates) 0.02 mg P/lthe location of the site is only approximateno unmet standard
  • Levočský potok č. 3SHMÚ site Levočský potok, ústie (9.2 km) · Prešov Regionthe location of the site is only approximateno unmet standard
  • Poprad č. 9SHMÚ site Veľká Lomnica (9.3 km) · Prešov Region · groundwater nearby within the standard (nitrates typically 0.5 mg/l)the location of the site is only approximateno unmet standard
  • Hornád č. 3SHMÚ site ÚKČ Košice, pod (10.6 km) · Košice Region · groundwater nearby within the standard (nitrates typically 24.3 mg/l)the location of the site is only approximateno unmet standard
  • Orava č. 1cSHMÚ site Orava, vyústenie OV z MAHLE Components a WWT Dolný Kubín, pod (12.4 km) · Žilina Region · groundwater nearby within the standard (nitrates typically 22.3 mg/l)the location of the site is only approximateno unmet standard
  • Poprad č.10SHMÚ site Veľká Lomnica (12.9 km) · Prešov Region · groundwater nearby within the standard (nitrates typically 1.9 mg/l)the location of the site is only approximateno unmet standard
  • Poprad č. 11SHMÚ site Veľká Lomnica (14.2 km) · Prešov Region · groundwater nearby within the standard (nitrates typically 4.1 mg/l)the location of the site is only approximateno unmet standard
  • Poprad č. 12aSHMÚ site Veľká Lomnica (16.5 km) · Prešov Region · groundwater nearby within the standard (nitrates typically 1.9 mg/l)the location of the site is only approximateno unmet standard

River basins from the cleanest

Share of SHMÚ sites that met all standards in 2025 (basins with at least 5 sites)

Cleanest sites on watercourses

No failed standard; more years in the yearbook means more reliable data

  • State borderPRAVOSTRANNÝ PRIES.K. /VDG/, rkm 0.0 · Danube basinthe location of the site is only approximate4 years in the yearbook, no unmet standard
  • Červený Kameň, nadTovársky potok, rkm 13.6 · Váh basinNearest fishing districts: Tovarský potok3 years in the yearbook, no unmet standard
  • Strážsky, ústie, nad cestný most Strážske-VoľaStrážsky, rkm 0.6 · Bodrog basinthe location of the site is only approximate3 years in the yearbook, no unmet standard
  • Tekovská BreznicaHron, rkm 88.9 · Hron basinNearest fishing districts: Hron č. 6a, Hron č. 7a, Hron č. 7bthe location of the site is only approximate3 years in the yearbook, no unmet standard
  • Starý Tekov – most (pod MVE)Hron, rkm 70.5 · Hron basin3 years in the yearbook, no unmet standard
  • Priečny potok, ústie (Demänovská dolina)Priečny potok, rkm 0.0 · Váh basin2 years in the yearbook, no unmet standard
  • PredpolomaPredpolomský P., rkm 5.2 · Váh basin2 years in the yearbook, no unmet standard
  • TopoľníkyKlatovské Rameno, rkm 3.0 · Little Danube and Žitný ostrov basinNearest fishing districts: Klátovské rameno č. 1, Klátovské rameno č. 22 years in the yearbook, no unmet standard
  • Ida, ústieIda, rkm 1.8 · Bodva basinthe location of the site is only approximate2 years in the yearbook, no unmet standard
  • Dem.Dolina, vyvieranieDemänovka, rkm 11.0 · Váh basinthe location of the site is only approximate2 years in the yearbook, no unmet standard
  • Orava, vyústenie OV z MAHLE Components a WWT Dolný Kubín, podOrava, rkm 19.5 · Váh basinNearest fishing districts: Orava č. 1a, Orava č. 1c, Orava č. 2athe location of the site is only approximate2 years in the yearbook, no unmet standard
  • Červený Kameň, pod ČOVTovársky potok, rkm 7.2 · Váh basinthe location of the site is only approximate2 years in the yearbook, no unmet standard
  • Bodva, odberný objekt VVS, nadBodva, rkm 41.8 · Bodva basinNearest fishing districts: Bodva č. 3, Bodva č. 41 year in the yearbook, no unmet standard
  • Nižný Lanec, nadPerínsky kanál, rkm 1.5 · Bodva basin1 year in the yearbook, no unmet standard
  • ČičarovceUdoč, rkm 2.8 · Bodrog basin1 year in the yearbook, no unmet standard
  • Smolník, ústieSmolník, rkm 0.0 · Bodrog basin1 year in the yearbook, no unmet standard
  • Hradenícky kanál, ústie do Čiernej vodyHradenícky kanál, rkm 0.0 · Bodrog basin1 year in the yearbook, no unmet standard
  • Petríkovce, mostBrehovský kanál, rkm 7.8 · Bodrog basin1 year in the yearbook, no unmet standard
  • Juskova Voľa, nadLomnica, rkm 9.0 · Bodrog basinNearest fishing districts: Lomnica (V n/T)1 year in the yearbook, no unmet standard
  • WWTP Slovnaft, belowDunaj, rkm 1,863.0 · Danube basinNearest fishing districts: Dunaj č. 3, Dunaj č. 3 – CHRO, Dunaj č. 3 – Rusovecko – Jarovecká sústava ramien and 1 more1 year in the yearbook, no unmet standard
  • Bystrá, nadHornád, rkm 165.2 · Hornád basinNearest fishing districts: Hornád č. 5b, Hornád č. 5c, Hornád č. 61 year in the yearbook, no unmet standard
  • KošiceČrmeľ, rkm 1.0 · Hornád basin1 year in the yearbook, no unmet standard
  • Kučmanovský potok, ústieKučmanovský potok, rkm 0.5 · Hornád basin1 year in the yearbook, no unmet standard
  • Odberný objekt VVS, nadHrabovec, rkm 10.8 · Hornád basin1 year in the yearbook, no unmet standard

Groundwater without an exceedance

SHMÚ monitoring stations, 2017 to 2025

Measured values: stations within the standard, 2025

363 of 758 stations (48 %) are within the standard: nitrates below 25 mg/l, no harmful substances, and no ammonium, nitrites, iron or chlorides above the limit.

  1. Žilina55 of 7573 %
  2. Prešov49 of 7070 %
  3. Trenčín42 of 7060 %
  4. Banská Bystrica56 of 9758 %
  5. Bratislava45 of 8156 %
  6. Košice50 of 11942 %
  7. Trnava40 of 12632 %
  8. Nitra24 of 11721 %

Stations with the lowest nitrates

  • Bilkove HumenceSenica district · borehole or well
    within the standard

    Measured values, year 2025, sampled 14 Apr 2025:

    • Nitrates< 1 mg/l
    • Ammonium0,03 mg/l
    • Nitrites0,03 mg/l
    • Iron0,003 mg/l
    • Chlorides< 1 mg/l
    • Selenium10% of the standard
  • BodikyDunajská Streda district · borehole or well
    within the standard

    Measured values, year 2025, sampling 16 Oct 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates< 1 mg/l
    • Ammonium0,23 mg/l
    • Nitrites0,02 mg/l
    • Iron0,28 mg/l
    • Chlorides21,6 mg/l
    • Arsenic68% of the standard
    • Methylbentazone60% of the standard
    • sum of PAHs16% of the standard
  • BratislavaBratislava I district · borehole or well
    within the standard

    Measured values, year 2025, sampled 13 May 2025:

    • Nitrates< 1 mg/l
    • Ammonium0,04 mg/l
    • Nitrites0,01 mg/l
    • Iron0,079 mg/l
    • Chlorides25,8 mg/l
    • Aluminium65% of the standard
  • BrekovHumenné district · borehole or well
    within the standard

    Measured values, year 2025, sampling 23 Sep 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates< 1 mg/l
    • Ammonium0,06 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,85 mg/l
    • Chlorides57,9 mg/l
    • Aluminium15% of the standard
  • Cebovce – Mala StudnaVeľký Krtíš district · source
    within the standard

    Measured values, year 2025, sampled 7 Jul 2025:

    • Nitrates< 1 mg/l
    • Ammonium0,16 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,78 mg/l
    • Chlorides81,6 mg/l
    • Aluminium15% of the standard
  • Chorvatsky Grob – Huc-1/1Senec district · borehole or well
    within the standard

    Measured values, year 2025, sampled 13 May 2025:

    • Nitrates< 1 mg/l
    • Ammonium0,01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,21 mg/l
    • Chlorides89,9 mg/l
    • Aluminium65% of the standard
    • Terbuthylazine-desethyl20% of the standard
  • ColtovoRožňava district · borehole or well
    within the standard

    Measured values, year 2025, sampling 14 Oct 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates< 1 mg/l
    • Ammonium0,13 mg/l
    • Nitrites0,02 mg/l
    • Iron0,2 mg/l
    • Chlorides96,6 mg/l
    • Arsenic17% of the standard
  • DobrohostDunajská Streda district · borehole or well
    within the standard

    Measured values, year 2025, sampling 24 Nov 2025 (4 samplings, the highest value of the year for each substance):

    • Nitrates< 1 mg/l
    • Ammonium0,02 mg/l
    • Nitrites0,02 mg/l
    • Iron0,61 mg/l
    • Chlorides19,2 mg/l
    • Lead16% of the standard
    • Methylbentazone80% of the standard
  • Gabcikovo-bakaDunajská Streda district · borehole or well
    within the standard

    Measured values, year 2025, sampling 16 Oct 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates< 1 mg/l
    • Ammonium0,04 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,036 mg/l
    • Chlorides22,5 mg/l
    • Aluminium20% of the standard
    • Methylbentazone30% of the standard
  • Gemersky JablonecRimavská Sobota district · borehole or well
    within the standard

    Measured values, year 2025, sampled 26 Jun 2025:

    • Nitrates< 1 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites0,03 mg/l
    • Iron0,33 mg/l
    • Chlorides27,5 mg/l
    • Nickel15% of the standard
  • Horna Ves – u HrantuŽiar nad Hronom district · source
    within the standard

    Measured values, year 2025, sampled 5 Jun 2025:

    • Nitrates< 1 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,38 mg/l
    • Chlorides1,4 mg/l
    • Aluminium30% of the standard
    • MCPB20% of the standard
  • Horny Bar-sulanyDunajská Streda district · borehole or well
    within the standard

    Measured values, year 2025, sampling 28 Oct 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates< 1 mg/l
    • Ammonium0,01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,027 mg/l
    • Chlorides44,1 mg/l
    • Aluminium15% of the standard
  • above the standard: nitrates from 50 mg/l, harmful substances or ammonium
  • nitrates from 25 mg/l, iron or chlorides high
  • within the standard

For each substance the value is the highest of the samples in the given year. A value equal to the standard counts as an exceedance, as in SHMÚ.

Share of stations without an exceedance in the 2025 yearbook, by region

  1. Trenčín48 of 7069 %
  2. Žilina52 of 7569 %
  3. Prešov40 of 7057 %
  4. Banská Bystrica46 of 9747 %
  5. Bratislava33 of 8141 %
  6. Košice45 of 11938 %
  7. Trnava23 of 12618 %
  8. Nitra10 of 1179 %

Stations that did not exceed the standard in any of the years 2017 to 2025

A sample of two stations from each region; there are 138 of 758 such stations in total.

  • Velke Pole – Studnasource
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampled 21 Jul 2025:

    • Nitrates19,3 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron< 0.002 mg/l
    • Chlorides12,2 mg/l
    • Aluminium15% of the standard
  • Ba-petržalka-mostBratislava V district · borehole or well
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 17 Sep 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates7,2 mg/l
    • Ammonium0,01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,002 mg/l
    • Chlorides25,8 mg/l
    • Aluminium95% of the standard
  • Plav.podhradie – RajtarkaMalacky district · source
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampled 23 Jul 2025:

    • Nitrates27,2 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,002 mg/l
    • Chlorides2,1 mg/l
    • Aluminium75% of the standard
  • MierovoDunajská Streda district · borehole or well
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 21 Oct 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates39,4 mg/l
    • Ammonium0,07 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,026 mg/l
    • Chlorides25,9 mg/l
    • Aluminium15% of the standard
  • MliecanyDunajská Streda district · borehole or well
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 17 Nov 2025 (4 samplings, the highest value of the year for each substance):

    • Nitrates21,3 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,02 mg/l
    • Chlorides31,9 mg/l
    • Aluminium15% of the standard
    • UCSN (Nikosolfurón)50% of the standard
  • C. Kamen – za Sipkovym 1Ilava district · source
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampled 21 May 2025:

    • Nitrates6,2 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites0,02 mg/l
    • Iron0,003 mg/l
    • Chlorides1 mg/l
    • Arsenic6% of the standard
  • TuchynaIlava district · borehole or well
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 24 Sep 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates18,6 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites0,01 mg/l
    • Iron0,003 mg/l
    • Chlorides16,7 mg/l
    • Aluminium15% of the standard
  • ZemliareLevice district · borehole or well
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 3 Nov 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates32,9 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,003 mg/l
    • Chlorides28,2 mg/l
    • Arsenic12% of the standard
  • Podhorany – Horna StudnaNitra district · source
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampled 18 Jun 2025:

    • Nitrates31,8 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron< 0.002 mg/l
    • Chlorides14,4 mg/l
    • Aluminium10% of the standard
  • Jablonove – pod RohomBytča district · source
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 8 Oct 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates1,6 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites0,02 mg/l
  • KotesovaBytča district · borehole or well
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 22 Sep 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates30,6 mg/l
    • Ammonium0,02 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,003 mg/l
    • Chlorides10,4 mg/l
    • Aluminium15% of the standard
  • Balaze – PodkalisteBanská Bystrica district · source
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampled 31 Mar 2025:

    • Nitrates3,2 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron< 0.002 mg/l
    • Chlorides< 1 mg/l
    • Aluminium5% of the standard
  • Banska Bystrica-majerBanská Bystrica district · borehole or well
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 16 Sep 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates1,5 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron< 0.002 mg/l
    • Chlorides35,5 mg/l
    • Aluminium15% of the standard
  • Chmelova – Podstavy 4Bardejov district · source
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 22 Sep 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates7,1 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
  • Krive – pod HorbiBardejov district · source
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampled 27 Mar 2025:

    • Nitrates3,8 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,023 mg/l
    • Chlorides2,7 mg/l
    • Aluminium10% of the standard
  • Kavecany – Pstruznik 1Košice I district · source
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampling 18 Sep 2025 (2 samplings, the highest value of the year for each substance):

    • Nitrates28,5 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
  • Drienovec-hlavnyKošice district – surroundings · spring
    no exceedance in 2025
    2017 to 2025

    In the yearbooks 2017 to 2025 no exceedance of the standard is recorded at the station.

    Measured values, year 2025, sampled 6 May 2025:

    • Nitrates16 mg/l
    • Ammonium< 0.01 mg/l
    • Nitrites< 0.01 mg/l
    • Iron0,003 mg/l
    • Chlorides9,5 mg/l
    • Antimony71% of the standard
  • substances from human activity
  • natural substances only
  • no exceedance recorded

Where the data come from and what they do not say

  • Surface waters: yearbooks of the Slovak Hydrometeorological Institute (SHMÚ) Surface Water Quality for the years 2022 to 2025. We transcribed the list of sites and indicators that failed the standard under Government Regulation no. 269/2010 Coll. into a table in the plugin. Older yearbooks are in a different format and we did not include them.
  • Groundwater: SHMÚ yearbooks Groundwater Quality, stations and indicators exceeded in 2017 to 2025 according to the drinking-water limits. The connection to the fishing district is only indirect.
  • Groundwater, measured values: the public SHMÚ interface "Groundwater quality monitoring results". We have actually measured values (nitrates, ammonium, iron, chlorides, metals, pesticides, PFAS, solvents) for 758 stations; for each substance we take the highest value from the samples in 2025 (for stations without data for that year, from one of the two previous years). A value equal to the standard counts as an exceedance, as it does at SHMÚ.
  • Treatment plants: register of wastewater treatment plants (VÚVH, EEA) from the "Points near fishing districts" file, that is, only plants within 2 km of the fishing district line. There are considerably more treatment plants in Slovakia.

What this data does not say. The yearbook lists the sites that failed the standard. A site missing from it is not proof of clean water, so the score of a fishing district is only ever lowered and never raised. We did not include industrial polluters (the National Pollution Register) in the list because the register was unavailable when the data was collected, and for wastewater treatment plants we list only those we found near the fishing districts. Only 31% of SHMÚ sites have an exact location, 47% have only an approximate location (based on the water body, so they count less near the districts) and 22% have no location at all, so we do not assign them to any district. We determine the distance, the match of the watercourse name and the ranking ourselves; the assignment is indicative.