Within the Karlovac water supply system, Borlin water plant is the most important cultural value, registered in the register of cultural goods of the Republic of Croatia.

It was built in 1914 according to the project of the Karlovac company A. Peyer and the other Vienna company Flegel, Karl and Stark. It consists of two wells (depth 20-22 m, diameter 0.8 m), two water reservoirs (150m³ in volume) and engine room, and supplied the first 16.5 km of pipeline network that stretched to the center of the city and to the Banija railway station (beginning of the industrial zone). Borlin industrial architecture is eclecticly shaped with elements of the secession and harmoniously complements the panorama of the former Karlovac, where residential and public buildings are in the same style. It has been restored to its 100th anniversary and is equipped with interpretative aids and open to the public.

These beginnings of the modern waterworks, which today counts 6 water wells and 650 km of water supply network, began preparatory work ten years earlier. At the end of 1906 Karlovac began exploring underground water supplies, and then Mayor Ivan Banjavčić advised with the highest geological authority of his time, Dragutin Gorjanović Kramberger. He wrote in the letter to the City Council of January 11, 1907 three alternatives for supplying potable water: supplying mountain water, using water from the Korana and drilling deep wells. The advantage was given to Borlin: the water from the source was taken from a depth of 6 to 24 meters and sent for analysis to the National Bacteriological and Hygienic Institute in Zagreb. It was found that Borlin “does not have a health complaint, so it can be recommended in all respects as healthy drinking water”. The composition of this water today is exactly the same as 100 years ago.

Drilling in Borlina was led by the city’s engineer Valerijan Rieszner, head of the city’s construction office. In 1913, the city purchased a private land with wells and neighboring Sladović courtyard for 60,000 crowns (formerly known as Vukasović’s courtyard, which was created at the time of designing the Lujzina Road when the general engineer Filip Vukasović had it built up for himself).
To the “public freight”, ie a public tender to build waterworks, companies from Vienna, Prague and Budapest were invited. Of the five bids received, a joint project of the Karlovac company A. Peyer and the other Vienna company Flegel, Karl and Stark were selected. The works started in September 1913 and on 10 November 1914 a laudation record was made – in today’s sense it was a positive technical review, and the city council accepted that record at the session of 21st November 1914. Construction of the city’s water supply amounted 406 405 crowns, and charge of water usage from the public started on 1 January 1915, according to the Commander and the price list for the use of water from the free and royal city of Karlovac.

Polović, Draženka; Radovan Radovinović. Hundred years of modern water supply in Karlovac. Karlovac: Water supply and sewage d.o.o. Karlovac, 2014.