With very few exceptions, the mills in the town center and the suburbs were water mills. The energy to drive the vast majority of mill wheels was supplied by the Taunus streams flowing down to the Rhine and Main, especially those that joined to form the Salzbach and Wickerbach streams. The Grorother and Weilburger Bach (Mosbach) joined them as further mill streams. However, the Salzbach alone deserved the name Mühlbach without restriction, as it supplied water to over 25 mill wheels at just eight mill sites. Even the path that accompanied the stream from the city center to the Rhine was originally called "Mühlweg" before it was given the name "Mainzer Straße". All five streams running along the Salzbach towards the Rhine provided around 40 water engines with the power to set the mill technology in motion. That was almost five-eighths of the total number of mills in the city today.

With over 60 water, animal and steam mills in operation, the milling industry in the city represented a considerable economic factor. However, neither the amount of grain harvested in the suburbs nor the number of consumers offered sufficient earning opportunities for so many mills, most of which were grinding mills. Many Wiesbaden mills therefore benefited from the fact that the 14 Rhine boat mills and 14 stream mills in Mainz alone were not able to supply the local population, the garrison, the flour merchants and the bakers sufficiently. This supply gap was exploited by both the Wiesbaden ban mills and the privately owned mills, thereby also contributing to the increase in the number of mills.

The oldest mills were used to grind grain and belonged to religious institutions, such as the Heilig-Geist-Mühle of the hospital of the same name (hence the name "Spitalsmühle") in Mainz, mentioned in 1259. This fourth mill on the Salzbach has been known as the "Spelzmühle" since the end of the 16th century. In the case of the lower mill on the Wickerbach, the name "Nonnenmühle" (nuns' mill), which was used at times, explicitly refers to this. Its existence, which dates back to 1272, is connected to the Altenmünster nunnery in Mainz. The Armenruhmühle belonging to the Klarenthal monastery and the "Klarenthaler Klostermühle", also owned by and close to the monastery, as well as that of the Eberbach monastery in Dotzheim are also among the earliest mills to be founded. It is questionable whether the Armenruhmühle on the Salzbach can be equated with a mill in Biebrich mentioned in a document as early as 992. Up to 1350, in addition to the four mills mentioned above, there is evidence of four other mills owned by the sovereign (Herrenmühle, Pletzmühle) and the nobility.

There was a focus on granting concessions for the construction of new mills in the years 1680-1720, which were encouraged by the building, foundation and commercial activities promoted by Georg August Samuel Prince of Nassau-Idstein. During his reign (1677-1721) alone, 19 new mills were built, such as the Hammermühle in 1690, the Neumühle in 1696 and the Steinmühle in 1704, all salt stream mills.

Wiesbaden had the highest density of mills between 1850-60. Some mills had already closed down by this time (such as the Firnselmühle in 1847) and a number had been converted into other businesses (the Walkmühle became a brewery in 1862). By the end of the decade, only four new mills had been established (Söhnlein tobacco cutting mill on the Grorother Bach in 1856, Dochnahl wood cutting mill on the Kesselbach in 1857, Rheinschiffmühle on the Rettbergsaue near Biebrich around 1860, Urban grinding mill on the Kesselbach in 1860). 32 of the total of 53 mills in 1860 functioned as grinding mills for grain. The second most important branch of the milling industry, the processing of oil fruits into cooking, lubricating and lighting oil, was already beginning to "wither away", as the city had replaced oil street lighting with gas in 1848. In addition, the emerging use of petroleum limited the use of rapeseed oil as an illuminant in commercial enterprises and households. In 1855, only eight oil mills still existed as an annex to a grain mill (Armenruh-, Dieten-, Grorother-, Hammer-, Hockenberger-, Kimpel-, Kurfürsten- and Neu-Mühle). Other non-grinding mills, such as the tan and fulling mills and the hemp grinders, also fell victim to newer processing techniques for leather and textiles. Only in the Junkermühle was there still a grinding process for the production of tanning liquor from oak bark. In the Nerotal mill, one wheel drove both a tanning and a fulling mill. Only in the former tan mill, now a grist mill, in Rambach was there still a hemp mill.

Other types of mills appeared at the same time. These included cutting mills for dyed wood (Michael Spangenberg in Rambach), fournier (Greuling & Weyghardt), timber (carpenter Dochnahl on Schwalbacher Straße, originally a water mill, later a steam mill) and tobacco(Johann Jacob Söhnlein at the mouth of the Grorother Bach). Peter Heppenheimer operated a grinding plant for plaster in the Kurfürstenmühle. At various mill sites, the water was used for wool processing (in Michael Diez's mill for wool spinning and in the monastery mill for artificial wool production), as a pumping station for spa operations (Nerotalmühle, Beau Site, and at the Guckuck cold water works on the Schwarzbach) and for starting up a threshing machine. The drive technology for all of these engines consisted of water wheels, 60% of which consisted of just one wheel. Depending on the weather and water flow of the streams, several mills on the Kesselbach, Rambach and Wickerbach could use two wheels.

The importance of the Wiesbaden mills can also be seen from the fact that some mills operated with more than two wheels. The Elector's Mill at the mouth of the Salzbach stream into the Rhine was the only mill in the Duchy of Nassau to have five water wheels, and even the three four-wheeled Salzbach mills dominated compared to only one of this type outside Wiesbaden (Brückenmühle in Weilburg). Together with three three-wheeled mills, these operations on the Salzbach enjoyed very good capacity utilization due to their technical equipment, but also because they were in operation all year round. They benefited from the fact that the Salzbach carried mineral-rich and warm water from the thermal springs, which meant that the stream did not freeze over in winter.

Several mills fulfilled different functions, for example as grinding and oil mills or as tan and fulling mills. Two of these multifunctional businesses in Rambach need to be explained. Michael Spangenberg ran a mill there with a grinding gear and another gear for cutting and grinding dye wood. This was probably white, yellow and red sandalwood imported from India and blue dyewood from Brazil. After further processing, the dye powder produced from these woods was used as a textile dye, as a wood stain and as a base material for medicinal mixtures against inflammation, to strengthen the heart and stomach, but also for the production of cosmetics due to its pleasant smell. The Stickel and Klarenthal mills also had dye wood mills for a time. In a former loam mill in Rambach, Jakob Zerbe II operated both a grain grinding mill and a mill to "grind" hemp. This was done with a grinding stone in the shape of a truncated cone rotating on a stone base, which made the hemp fibers soft and supple. In 1824-46, the Reitzenmühle in Auringen also had a rubbing mill for flax.

The Rhine mill near Biebrich was a rare mill facility for Wiesbaden. This ship mill anchored at Rettbergsaue functioned as a grinding mill. Such Rhine ship mills were mainly found where stream mills were not particularly efficient due to the flat terrain.

Often the owner of a mill was also its operator, but not everyone who operated a mill was also its owner. In 1845, for example, Colonel Karl Friedrich Ebhardt acquired the paper mill in Klarenthal Monastery, which had not been put back into operation after a fire in 1840, and leased it to a miller who set up a grinding mill there. Well-running mills and those that were sold by (forced) auction often proved to be sought-after investment properties. Conversely, mill owners or users could also make a considerable profit by selling them. Hammer miller Bernhard May, for example, succeeded in doing so when he acquired the right to use the copper mill on the Salzbach for his only son for 15,000 fl. in 1830. After his son died in 1834, May sold the mill to miller Adam Werner for 25,000 fl. Many mills in Wiesbaden were owned by the respective sovereigns. They lent the upper ownership of these properties - called "dominium directum" - to interested millers as sub-ownership for their use ("dominium utile"). This right of use, known as "Erbleihmühlen", existed until it was redeemed in 1869. Some Erbleihmühlen millers had already succeeded in acquiring unrestricted ownership rights by paying 20 times the annual rent, such as Bernhard May of the Hammermühle for the price of 5,562 fl., Christian Bertram of the Dietenmühle for 6,635 fl. and Nikolaus Werner of the Kupfermühle for 7,000 fl. For various reasons, the town, societies and companies showed interest in acquiring larger mill sites, such as the Kurhausgesellschaft. It acquired the Firnselmühle in 1845 in order to use the water supply for the Kurhaus fountain that was to be built.

Some hereditary mills, especially those owned by the sovereign, had the status of a ban mill. They had the right to grind grain for the inhabitants of a certain district (villages, farms) without interference from a competitor. This centuries-old privilege had such an effect in the city and its present-day suburbs that in 1750, for example, the city center was banned to the Herrenmühle and the Pletzmühle, Erbenheim to the Spelzmühle, and Biebrich and Mosbach to the Armenruhmühle as early as 1344. Some millers obtained a ban district by buying it from a colleague who was banned, as the operator of the road mill in Dotzheim did in 1735. He bought the ban over Schierstein from the stone miller at Salzbach for 300 fl. Private mills without a ban could not dispose of a fixed number of grinding customers. They had to try to win customers in towns without a ban, trade in the milled products they produced at markets or improve their earning potential by doing additional business, such as oil milling.

Where no body of water provided the energy to drive the mill technology, animals - and after 1860 steam engines in some cases - replaced the work of the water. Breweries occasionally used a horse to crush the malting barley. In Biebrich in the second half of the 18th century, there was a horse mill for cutting and grinding tobacco leaves and a tobacco and oil mill where oxen were used to drive the mill. The extension of the term "mills" to "water-powered mills" makes it possible to include installations that had water wheels, but not grinding, stamping, crushing, cutting or grinding equipment. In Wiesbaden, this category includes two pumping stations for bathing facilities in the Nero valley in 1851 and 1858. One of these emerged from a tannery and fulling mill - later the Beau Site inn - the other from a cloth factory with fulling and spinning facilities - subsequently called the "Nerotal Sanatorium". There were also two other water-powered mills, which were set up for spinning wool.

The use of steam engines offered a real alternative to water power in the service of the mills. Miller Johann Heppenheimer in the Kurfürstenmühle at the mouth of the Salzbach made a start in 1860. In the following decades, steam engines were also used in the Herrnmühle (Herrnmühlgasse), in the Kupfermühle (on the Salzbach), in the Hockenberger Mühle (in Kloppenheim) and in a wood-cutting mill (between Biebrich and Schierstein). Some millers continued to use water power, while others converted their operations entirely to steam power. This was reflected in the company name "Dampfmühle" (steam mill). The Wagemann steam mill (Kimpelmühle, in Metzgergasse) was one such company. Technical and structural changes in and to mills usually only took place after 1860. Improvements originating in America, England and France (conveyor systems, use of cast iron, replacement of wooden water wheels with turbines) were initially only used by the larger companies.

Improvements in mill technology were usually only made in the suburbs in the 20th century. This only affected around a quarter of all mills, as most of them, especially in the city center, were unable to survive beyond the turn of the century. Those that were still in operation after 1900 included the road mill on the Mosbach, the Armenruh, copper and stone mills on the Salzbach and the Untermühle on the Wickerbach. There were also two mills that remained the last active mills in Wiesbaden until the 1950s: the Hockenberger Mühle between Kloppenheim and Medenbach and the Obermühle in Igstadt.

It took 600 years (until 1860) from the first mention of a mill to the last approved one. The decline took place much faster in just 120 years (1840 to around 1960). There were various reasons for the standstill, the change in function and the demolition of the mills. The numerous mill fires and the devastation caused by war motivated reconstruction rather than resignation. One example of this is the Obergrundmühle. This mill near Dotzheim burned down completely in 1857. After being rebuilt the following year, it continued to grind flour and also made a name for itself as an excursion destination. The copper mill on the Salzbach was even worse off. It fell victim to fires several times (1644, 1845, 1878, 1896). Nevertheless, it managed to survive as a grist mill with an attached bread factory until the 20th century. The decline of numerous stream mills in Wiesbaden between 1850 and 1900 was caused by the increase in large mills at wet locations on the coast, but also on the Rhine. The increasing restriction of arable land and the associated decline in grain production contributed to the disadvantage in the city and the surrounding area. Urban development measures, such as progressive building development, expansion of the road network, creation of facilities and health resorts, but above all canal and sewage treatment works, interfered with the mill population.

The compensation paid by the town and the Kurhausgesellschaft for mill sites probably had a significant influence on the mill owners accepting offers from the municipality and commercial enterprises and leaving their sites. In 1857, for example, the company Chemische Werke Albert acquired the Lohmühle on the Mosbach to set up a chemical factory. In 1859, the Kurhausgesellschaft bought the Pletzmühle on the Kesselbach, demolished it and created the park-like grounds of the Warme Damm on the Mühlenplatz. In 1860, the Erkelsmühle, also located on the Kesselbach, was purchased by the town to extend the road at the "Stumpfen Tor". In 1884, the Spelzmühle on the Salzbach had to make way for the construction of the sewage treatment plant. With the sale of the salt mill to the Gademann company in 1845, the water supply was retained, but the flour mill was lost. It made way for an artificial wool spinning mill, which in turn made way for a woodworking factory a few decades later. Through such expansions and conversions, several mills became the nuclei of (large) bakeries (Armenruh-, Hammer- and Kupfermühle am Salzbach, Kimpelmühle in Metzgergasse), commercial and industrial enterprises (artificial fertilizer and glue factory Gebr. Albert in the Lohmühle, plastics factory Kalle in the Kurfürstenmühle, printing and publishing house in the Herrnmühle) as well as inns. Representative of more than ten former and still existing mill inns are Beau Site, formerly Nerotalmühle, "Waldhorn" in the former Klarenthaler Mühle, Café-Restaurant Dietenmühle with Milchkuranstalt and Schleifmühle Bacchus in Aarstraße.

Among the operators/owners of the mills, some of which were multi-functional and included agriculture, some stood out for their personal prestige, cleverness and wealth. This could be expressed, for example, by the fact that they managed to own/operate several mills at the same time, such as Fritz Späth (Armenruh mill, hammer mill and salt mill) or Johann Kreckmann (Erkels mill and stone mill). Others added another business to their grinding mill: Karl Wagemann added a bakery to his grinding mill, Adam Volz added an oil press to his grinding mill. Still others were able to utilize the water power for special tasks by adding an annex to their main business: Johann Heppenheimer added a plaster mill and a sawmill to his grist mill, Bernhard May also used the water power of his grist mill to drive a threshing machine. Some of those mentioned also made a name for themselves as (local) politicians: Johann Heppenheimer as mayor of Biebrich, Bernhard May as a member of the Frankfurt pre-parliament and as a participant in the Hambach Festival, Jean Baptiste Wagemann as a town councillor and town elder.

The prosperity of some millers is also documented by the amount of trade tax they paid. Around 1850, the highest-taxed tradesmen in Wiesbaden included: the poorhouse miller Johann Heppenheimer and his son, the electoral miller Peter Heppenheimer, stone miller Adam Volz, copper miller Nikolaus Werner, kimpel miller Karl Wagemann, new miller Philipp Poths and, above all, hammer miller Bernhard May. In 1854, he paid by far the most tax among the "highest taxed tradesmen". But the miller families were not spared the blows of fate either. This was particularly true at times when the effects of war (Dietenmühle, Klostermühle, Salzmühle) or fires (Gerbermühle 1667, Klarenthaler Mühle 1840, Hammermühle 1843, Straßenmühle 1848 and several others) impaired the millers' activities. Such disasters date back to the recent past. In the last war, bombs hit the Herrnmühle and the Straßenmühle, where there were also fatalities.

Natural events made life difficult for many a miller. For mills on the upper reaches of streams, this took the form of a lack of water. The Obergrundmühle and the Sonntagsmühle on the Weilburger Bach near Dotzheim are examples of this. In 1829, Heinrich Wintermeyer called his mill (Sonntagsmühle) not very productive. In order to be able to hold his own, he worked as a carter in the service of the community. At the road mill, also in Dotzheim, a landslide buried the mill ditch and led to the grinding business being discontinued in 1927.

None of Wiesbaden's mills are still in operation. In the suburbs, former mill buildings are still used as residential buildings, for agriculture, animal husbandry and horticulture (Auringer Mühle, Hockenberger Mühle/Kloppenheim, Kingenmühle/Breckenheim, Obermühle/Igstadt, Reitzenmühle/Auringen, Untermühle/Igstadt). A few inns are still adorned with the suffix "mill", such as the Hockenberger Mühle, the Klostermühle, the Schleifmühle and the Straßenmühle. However, street names are the most striking reminders of the town's long mill history. The city map shows more than 20 such names in the city center and the suburbs. The name "Mühlradgasse" for a street in Rambach or "Mühlgartenweg" in Breckenheim sounds almost poetic. Other street signs mention former mills by name: "An der Dietenmühle" or "Straßenmühlenweg". Street names also refer to the names of some mill owners: Bernhard-May-Straße, Heppenheimerstraße, Söhnleinstraße and Wagemannstraße