Lake Constance — Water balance
All known inflows and outflows of this lake with their current discharge — and the balance that results: is more water flowing in right now than out, or the other way round?
Live from 19 readings
Measured water balance
Updated 17 minutes ago
How to read the water balance: it is the difference between measured inflow and outflow, in cubic metres per second. A positive value means more water currently enters the lake than leaves it (it tends to rise), a negative value the opposite. It is a partial balance – not every tributary has a station, and rain on the lake surface, evaporation, groundwater and regulation are not fully captured. The balance therefore shows the tendency, not an exact volume calculation. The swimming-pool comparison only illustrates the order of magnitude.
Where does the water come from?
Where does it flow to?
Rain and inflow
How Rhein, Oberriet (Zufluss) responds to rainfall over the last 30 days.
- Rain
- Rhein, Oberriet (Zufluss)
How to read: the bars show daily precipitation in the catchment (mm, left axis), the line the largest measured tributary (right axis). This shows whether and how quickly the lake responds to rain – inflow usually follows precipitation with some delay.
Drinking water from the lake
Annual figures, as of 2024-10Around 5M people drink water from this lake; 17 utilities draw it. Unlike inflow and outflow these are not continuous measurements but published annual figures — shown here in the same unit as the balance above so both can be compared directly.
5.39 m³/s
Actual extraction
1.5 % of inflow
4.25 m³/s
Removed from the lake
1.2 % of inflow
10.65 m³/s
Permitted maximum
2.9 % of inflow
361.50 m³/s
Total inflow
Tributaries and precipitation
All drinking water extraction together amounts to 1.5 % of what flows into the lake. Even if every permit were used in full it would be 2.9 %. Much of the extracted water also returns to the lake after treatment. For the lake level, the outflow, hydropower use and weather matter by orders of magnitude more than drinking water.
Largest single abstractor: Bodensee-Wasserversorgung with 4.12 m³/s.