Stations are listed from source to mouth as the water flows, traced on the river map (OS Open Rivers) and the Environment Agency’s own links between its gauges. A distance “by river” is along the river, and is shown only where the map traces the path.
Streams and rivers with a gauge whose water joins the Ayr above one of its gauges, from the source down. Named streams without a gauge that have a page here are listed at the end.
Named streams on the river map that flow into the Ayr and have no gauge of their own. Each has a page with what is known about it: the next gauge downstream, and any storm overflows or water-sampling points placed on it.
26 storm overflows are traced upstream of Mainholm, the Ayr’s lowest gauge on the river map: on the Ayr itself, on its gauged tributaries, and on smaller streams that join above there.
0 report discharging now
24 not discharging
2 offline or silent: 2 monitor offline, 0 status unknown, 0 no live feed
Official figures for 2025, for the overflows traced upstream of Mainholm: 2,450 overflow events over 6,052 hours in total, across the 14 that have a figure. 3 had no data that year; 9 have no 2025 figure. Scottish Water counts overflow events, not the 12/24-hour spills counted in England and Wales, so this total cannot be set beside theirs.
Each overflow is listed in the stretch above the first gauge its water reaches, from the source down, as on the Gauges tab. A stretch of the Ayr includes the smaller streams that join it there.
Above Wellwood, the Ayr’s highest gauge3 overflows
Muirkirk, Muirkirk SPS No3 PcsoNot discharging Scottish Water · into River Ayr · 5.3 km by river above Wellwood · no official annual figure
Muirkirk, Muirkirk No1 SPS CSONot discharging Scottish Water · into River Ayr · 3.8 km by river above Wellwood · no official annual figure
Muirkirk WwTW SssoNot discharging Scottish Water · into River Ayr · 2.7 km by river above Wellwood · 2025: no data
Between Limmerhaugh and Catrine2 overflows
Catrine, Institute Avenue CSONot discharging Scottish Water · into River Ayr · 310 m by river above Catrine · no official annual figure
Catrine, 15 Bridge Street SwoNot discharging Scottish Water · into River Ayr · 290 m by river above Catrine · no official annual figure
Between Catrine and Mainholm13 overflows
Ochiltree WwTW - Inlet CSONot discharging Scottish Water · into Lugar Water · 31.2 km by river above Mainholm · 2025: no data
Ochiltree WwTW - 6dwf CSONot discharging Scottish Water · into Lugar Water · 31.2 km by river above Mainholm · no official annual figure
Catrineholm WwTW CSONot discharging Scottish Water · into River Ayr · 28.7 km by river above Mainholm · 2025: 117 overflow events, 277 h
Mauchline, The Haugh/Haugh Rd CSOMonitor offline Scottish Water · into Tributary Of River Ayr · 25.3 km by river above Mainholm · 2025: 0 overflow events, 0 h
Mauchline WwTW-Treated 1.5dwf SssoNot discharging Scottish Water · into River Ayr · 24.9 km by river above Mainholm · 2025: 617 overflow events, 2,787 h
Tarbolton SPS CSO Ns429277Not discharging Scottish Water · into Tributary Of Water Of Fail · 23.9 km by river above Mainholm · 2025: 1 overflow event, 0.3 h
Tarbolton SPS EO Ns429277Not discharging Scottish Water · into Tributary Of Water Of Fail · 23.9 km by river above Mainholm · 2025: 1 overflow event, 0.2 h
Drongan WwTW Pst SssoNot discharging Scottish Water · into Water Of Coyle · 18.6 km by river above Mainholm · 2025: no data
Coylton WwTW (Inlet) CSONot discharging Scottish Water · into Byres Burn · 11.2 km by river above Mainholm · 2025: 12 overflow events, 7.9 h · placed on the river by its position alone
Coylton WwTW CSO (Screened)Not discharging Scottish Water · into Byres Burn · 11.2 km by river above Mainholm · 2025: 22 overflow events, 25 h · placed on the river by its position alone
Annbank, Annbank STW (6 Dwf) CSONot discharging Scottish Water · into River Ayr · 5.6 km by river above Mainholm · no official annual figure
Lugar Water, above Langholm Ajoins the Ayr above Mainholm8 overflows
Cumnock, Lugar SPS CSONot discharging Scottish Water · into Lugar Water · 11.6 km by river above Langholm A · 2025: 1,288 overflow events, 579 h
Cumnock, 1 Holm/Lugar Bridge CSONot discharging Scottish Water · into Lugar Water · 8.6 km by river above Langholm A · no official annual figure
Cumnock, 92 Ayr Road CSONot discharging Scottish Water · into Lugar Water · 8.2 km by river above Langholm A · no official annual figure
Cumnock, 28 Harperbank Grove/AcademyMonitor offline Scottish Water · into Lugar Water · 7.7 km by river above Langholm A · no official annual figure
Cumnock, Bankend SPS CSONot discharging Scottish Water · into Tributary Of Lugar Water · 7.7 km by river above Langholm A · 2025: 0 overflow events, 0 h
Cumnock, Underwood STW (9 Dwf) CSONot discharging Scottish Water · into Lugar Water · 7.2 km by river above Langholm A · 2025: 50 overflow events, 123 h
Auchinleck, Bridgend SPS CSONot discharging Scottish Water · into Auchinleck Burn · 6.8 km by river above Langholm A · 2025: 8 overflow events, 9.3 h
Cumnock Underwood STW (3 & 6 Dwf) CSONot discharging Scottish Water · into Lugar Water · 6.8 km by river above Langholm A · 2025: 121 overflow events, 1,038 h
Near these gauges, connection not known
Within 3 km of one of the Ayr’s gauges in a straight line, but the river map cannot say whether their water reaches it.
Ayr, 2 George Street CSONot discharging Scottish Water · into River Ayr · 2.3 km from Mainholm in a straight line · discharges into a tidal reach, where the water moves both ways · 2025: 1 overflow event, 0.5 h
St. Quivox, Hannah Research Inst CSONot discharging Scottish Water · into Tributary Of Ladykirk Burn · 2.6 km from Mainholm in a straight line · its watercourse is not on the river map · 2025: 0 overflow events, 0 h
4 other overflows within 3 km of these gauges are placed below the Ayr’s lowest gauge or on another river, so not listed.
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