A current utility snapshot can show scale, but it cannot reveal whether that scale is new, stable or changing. Berliner Wasserbetriebe's compatible 2020–2025 evidence adds that missing dimension while preserving the limits of what annual figures can support.
Waterworks production capacity rose from 1.0 million cubic metres per day in 2020 to 1.1 million in 2022. It then remained at the reported 1.1 million level through 2025. The current capacity is therefore not a new 2025 expansion.
Water sales followed a different path. Annual sales moved from 223 million cubic metres in 2020 to 217 million in 2025, with movement in both directions during the intervening years. The sequence does not justify a single causal explanation based on weather, population, price or conservation.
Wastewater treatment volumes also varied rather than following a continuous rise or decline. This matters because annual throughput reflects multiple operating and environmental conditions. Trend language should remain proportionate to the observed pattern.
Network change was gradual relative to total system size. Drinking-water network length increased by about 0.83 per cent across the period, while total sewer length rose by about 0.31 per cent. Those measures describe net length, not the amount of infrastructure renewed or the condition improvement achieved.
The combined sewer network remained at the same published length throughout the six-year series. That continuity helps explain why stormwater retention and blue-green measures must operate alongside a persistent legacy configuration rather than assume rapid replacement.
The financial history is less stable. Revenue increased across the full period, while the 2025 operating and net results moved into negative territory after positive earlier years. The evidence establishes a discontinuity but does not establish its complete causes.
Fixed assets rose between 2020 and 2024 before easing in 2025. Reading only the first and last values would show long-run growth; reading only the latest annual movement would show decline. Both are true, and neither should erase the other.
Historical compatibility is what makes these comparisons defensible. Observations are joined only when definition, scope, unit, basis and reporting period are sufficiently aligned. Possible older extensions were withheld where that alignment could not be proved.
This approach preserves sparse or limited history without turning missing years into estimates. A series is useful because its members are compatible, not because it reaches a preferred length or produces a visually smooth chart.
The full report uses this historical layer to test current investment and forward commitments. Berliner Wasserbetriebe DATA allows readers to inspect the exact compatible observations and the points withheld from series formation.