We test the River Tamar weekly at two locations near Calstock. Our laboratory analysis measures E. coli and Intestinal Enterococci levels to help you understand water quality and make informed decisions about river use.
The chart below shows bacteria levels over time at our sampling sites. Green lines indicate excellent water quality thresholds, while yellow lines show good quality limits according to EU Bathing Water standards.
| Date | Site | E. coli (cfu/100ml) | Enterococci (cfu/100ml) |
|---|---|---|---|
| 29/09/2025 | Calstock | 320 | 104 |
| 29/09/2025 | Okel Tor | 280 | 92 |
| 15/09/2025 | Calstock | 2400 | 4300 |
| 15/09/2025 | Okel Tor | 4300 | 4800 |
| 01/09/2025 | Calstock | 2700 | 480 |
| 01/09/2025 | Okel Tor | 220 | 79 |
| 26/08/2025 | Okel Tor | 280 | 64 |
| 26/08/2025 | Calstock | 180 | 84 |
| 18/08/2025 | Calstock | 390 | 98 |
| 18/08/2025 | Okel Tor | 550 | 59 |
| 11/08/2025 | Okel Tor | 270 | 113 |
| 11/08/2025 | Calstock | 310 | 118 |
| 28/07/2025 | Calstock | 220 | 98 |
| 28/07/2025 | Okel Tor | 240 | 61 |
| 18/07/2025 | Okel Tor | 72 | 56 |
| 18/07/2025 | Calstock | 48 | 29 |
| 09/07/2025 | Calstock | 490 | 300 |
| 09/07/2025 | Okel Tor | 250 | 72 |
| 02/07/2025 | Okel Tor | 130 | 81 |
| 02/07/2025 | Calstock | 140 | 71 |
Showing most recent 20 results of 80 total samples
E. coli and Enterococci are indicator bacteria used worldwide to assess water quality. Higher levels suggest increased risk of waterborne illness.
EU Bathing Water Quality Standards:
Important: These are single-point measurements. Official bathing water classifications use multiple samples over four years. Always check recent rainfall and storm overflow status before entering the water.
Daily pollution risk forecasts for Plymouth bathing waters provide a proxy indicator for Tamar water quality. These Environment Agency forecasts predict short-term water quality impacts from rainfall and storm overflows.
⚠️ These are single-day forecasts. Always check recent weather and storm overflow status before water activities.
Data: Environment Agency Bathing Water Pollution Risk Forecast • © Crown Copyright, licensed under the Open Government Licence v3.0
Real-time environmental conditions affecting water quality in the River Tamar near Calstock. These core indicators show river flow, tidal state, rainfall, and storm overflow activity. Note: Comprehensive contamination risk assessment requires additional metrics including wind conditions, sunlight/UV exposure, seasonal factors, water temperature, and turbidity measurements. Always consider multiple environmental factors before water activities.
High flow indicates recent rainfall, increasing contamination from agricultural runoff and urban drainage.
Low tide concentrates pollution, high tide provides dilution. Check tide state before water activities.
Heavy rainfall triggers agricultural runoff and storm overflow discharges. Avoid water contact 48-72 hours after heavy rain.
Active CSOs discharge untreated sewage. Always check current status before entering water.
| Location | Started | Duration | Status |
|---|---|---|---|
| Loading events... | |||
• River & Tide Levels: Environment Agency real-time API • Updated ~15 min
• Rainfall: Environment Agency Rainfall API • Open Government Licence v3.0
• Storm Overflows: South West Water EDM (Stream) • CC BY 4.0 • Updated ~10 min
Check live storm overflow status before swimming or paddling