River Cam & drought watch

How the River Cam is flowing compared with normal for the time of year — a live Environment Agency signal of how dry things are getting, with Cambridge Water's hosepipe-ban status alongside.

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Cam · Dernford, on the Cam a few miles south of the city near Sawston

0.25 m³/s

The Cam is running low for the time of year. Rising over the past couple of weeks. Daily mean for Friday 9 October.

Around the 14th percentile of October flows on record. That is about 62% of the normal October flow.

0.25 m³/s

Flow now

latest daily-mean discharge

0.29 m³/s – 0.62 m³/s

Typical for the month

the usual middle range in October (25th–75th percentile)

0.40 m³/s

Normal for the month

the long-term median October flow

Worth knowing

Why the Cam runs low in summer — and why it matters

The Cam is a chalk river. In a dry summer it naturally drops to a fraction of its winter flow, and the chalk aquifer that keeps it going is the same source about 97% of Cambridge's drinking water comes from. That makes this one of the least water-secure cities in the country: when the river is low, the aquifer behind it is under strain too. The proposed Fens Reservoir is years away, so for now the pressure is real every dry summer.

What this does and doesn't tell you

This page shows how the river is flowing day to day, compared with its own long-term record for the month. It is not a drought declaration and not a decision about water restrictions. The official drought status is set by the Environment Agency, and any hosepipe ban is Cambridge Water's call — both are linked below. A low reading here is a sign of a dry spell, not a forecast of one.