At KnotNow, we integrate real-time sewage discharge data into your forecast to help you decide if the conditions at Calshot, Hampshire are right and whether it's not now or KNOTNOW and for more than just the wind.
While we track whether each storm overflow and sewage overflow is operating or not, this data is just one piece of the puzzle. Factors like tide state, current direction, and UV levels all impact how a sewage discharge disperses. We provide this transparency to help you make informed decisions, but always trust your judgment and check local conditions on arrival.
We track all active storm overflow and sewage discharge events within a 3km radius of Calshot. We use straight-line distances as a precaution, though tide and wind can influence how discharge moves relative to the shore. This data is provided as a tool to help you assess the conditions before you head out.
When sewage discharge events are shown, we display the distance to each outflow (e.g. "Hamble – 2.4 km away") so you can judge the relative risk.
Our "ACTIVITY IN 48 HRS" flags any outflow that has been active within the last 48 hours. If a sewage discharge started prior to that window and is still ongoing (or only recently stopped), the total duration shown will exceed 48 hours.
When a location reports multiple stop-and-start events within 48 hours, we combine them into a single discharge event with a total duration. In practice, brief gaps between reported events may not mean the water was clear—the sewage overflow may have continued between those signals. We err on the side of caution and combine events to give you the fullest picture of activity at each outfall.
The general rule of thumb is to allow a 48-hour clear window after a discharge ends before hitting the water. If you're seeing high numbers, it might be a good day to check your kit or grab a coffee instead of a session.
This dashboard provides a direct feed of storm overflow and sewage discharge status and historical activity. However, data alone cannot guarantee water safety. We provide this transparency to help you make informed decisions, but always trust your judgment and check local conditions on arrival. After heavy rainfall, always exercise extra caution as storm overflows are most likely to be active during these periods.
Wind and weather forecasts for Calshot are provided to help you plan your sessions. Conditions at this coastal location can change quickly, so always check the actual conditions when you arrive and trust your judgment. These forecasts are for recreational planning—always prioritize safety and verify conditions yourself before heading out. Tidal predictions for Calshot are based on the nearest primary station at CALSHOT CASTLE (0.37km away). Local conditions can vary from these predictions due to coastal topography and weather effects. Always verify tidal conditions on arrival—these predictions are for planning purposes only, not for navigational use or critical safety decisions.