🏭 Hydrometer A.G. Summary

Hydrometer Breslauer Wassermesser‑Fabrik A.G. was one of Germany’s most influential water‑meter manufacturers of the early 20th century.

Founded in 1912 in Breslau, German Empire (now Wrocław, Poland), it emerged from the metering division of Neptun‑Werke, a mechanical engineering firm specializing in pumps and valves. (Not as a successor to Breslauer Metallgießerei or Breslauer Wassermesser‑Fabrik A.G.). It purchased castings from both Breslau foundries, produced complete meters and expanded to Mannheim. Became Hydrometer Group in 1991, and today forms part of Diehl Metering.

Hydrometer pioneered precision water‑meter technology, later expanding into heat‑metering and radio‑based remote reading systems.

Its lineage continues today under Diehl Metering, headquartered in Ansbach, Germany.

🏭 Neptun‑Werke (1862–1912)

Established in 1862 in Breslau, Neptun‑Werke produced industrial pumps, valves, and early flow‑measurement devices.

By the 1890s, Neptun had developed mechanical water‑meter prototypes for municipal waterworks.

Its metering division became increasingly specialized, leading to the creation of a dedicated company.

Formation of Hydrometer (1912)

In 1912, Neptun‑Werke reorganized its metering division as Hydrometer Breslauer Wassermesser‑Fabrik A.G.

The new company focused exclusively on precision water‑meter manufacturing, adopting the name Hydrometer (from Greek hydro = water, metron = measure).

Hydrometer’s early meters featured oscillating piston mechanisms, multi‑dial registers, and brass housings cast by local foundries such as Breslauer Metallgießerei (Guttsmann Group). ⭐ Hydrometer’s operations included:

✔ Designing complete water meters

✔ Manufacturing mechanisms

✔ Producing multi‑dial registers

✔ Calibrating meters for municipal waterworks

✔ Exporting meters across Germany and Europe

✔ Purchasing castings from Breslau foundries

Hydrometer did not cast its own bodies. Instead, it sourced castings from:

Breslauer Metallgießerei (H. Wolff & Schreiber) and Breslauer Wassermesser‑Fabrik A.G.

✔ Hydrometer sold complete meters to Breslauer Wasserwerke

Hydrometer was commercially connected, not corporately connected to the above two entities.

⭐ Expansion and Relocation (1930s–1950s)

As Breslau’s industrial landscape changed (especially post‑WWI), Hydrometer:

- expanded production

- modernized mechanism designs

- increased exports

- relocated major operations to Mannheim, Germany

This relocation marks the beginning of Hydrometer’s transformation into a national‑scale manufacturer. After WWII, Hydrometer expanded production and later relocated from Breslau to Ansbach, Bavaria in the early 1950s. ⭐ The DDR Era (1946 -1990)— VEB Hydrometer (East Germany)

During the East German socialist period, Hydrometer operated as a VEB (Volkseigener Betrieb) — a state‑owned enterprise.

⭐ Hydrometer Group (1991)

In the late 20th century, Hydrometer consolidated its operations into producing:

- water meters

- heat meters

- flow sensors

- electronic metering systems - introduced the IZAR radio system for remote meter reading.

Hydrometer Group became one of Europe’s most recognized metering brands.

The move positioned Hydrometer within West Germany’s industrial recovery, enabling modernization and export growth.

⭐ Acquisition and Modern Era (2000s–Present)

Hydrometer Group was eventually integrated into:

Diehl Metering, a global metering and smart‑infrastructure company.

Hydrometer remains a brand lineage within Diehl Metering, with its Breslau origins still acknowledged in historical literature. 🏛️ Summary Statement

Hydrometer Breslauer Wassermesser‑Fabrik A.G. (founded 1912) originated from Neptun‑Werke’s metering division in Breslau.

It became a cornerstone of European water‑meter engineering, evolving through mechanical, electronic, and smart‑metering eras.

Today, its lineage continues under Diehl Metering, preserving over a century of precision craftsmanship and innovation. Note: Historical Water Meter pictures courtesy of < 19_willy_93 > , there you will find possibly the largest collection of historic German origin water meters anywhere in the world.