The water of Paranhos is mentioned in a Royal Charter issued by Queen Teresa in 1120 and in a Royal Charter issued by King Afonso Henriques in 1138. These charters also mention the “Canallem Maiorum,” the largest canal, which is currently known as the Rio de Vila, as it was named during the reign of Afonso IV, and the city's other river, the Rio Frio.

The 1392 Book of Council Meetings refers to the existence of public fountains in the city, discussed in a City Council session due to the contamination of their waters, and constitutes the oldest known written reference.

The first known references to the water of Mijavelhas date back to the 15th century and indicate the existence of a fountain. As for the Mijavelhas Manancial, the first known reference dates back to 1548. 

King Filipe I issues the charter that drives the construction of the Paranhos Water Source, with an investment of 1,000 cruzados donated by the people of Porto. The first stone was laid in 1603. 

The water from this spring began to be exploited in 1619 for use in various mines, and a fountain was built for this purpose that same year. That year, the Fonte do Rio Frio (Cold River Fountain), known as Fonte das Virtudes (Fountain of Virtues), was built. It was believed that the waters had medicinal properties that could cure diseases.

During the Middle Ages, the river was a dumping ground for garbage and waste. To control the growing contamination, part of its flow was piped in 1763, and Rua de São João was built. The remaining flow was piped in 1875 when Rua de Mouzinho da Silveira was opened. 

In 1789, construction began on an aqueduct that would increase the flow of water reaching the city from the Salgueiros Spring. In 1838, this water reached the Arca de Sá de Noronha, in Praça Gomes Teixeira, which distributed it to the city.

The concession contract for the construction of Porto's first domestic water supply system was signed with a Parisian company, Compagnie Générale des Eaux, in 1882. Construction work took place between 1884 and 1886, and by 1887 the system was fully operational. 

The industrial home supply system becomes fully operational, powered by steam machinery operating in Porto's first industrial water architecture.

In 1897, a tender was opened for the construction of Porto's first industrial sanitation system, and in 1903, work began with the London-based company Hughes & Lancaster, continuing until 1916. 

They merged the water supply and sanitation services, inheriting the two systems dating back to the 19th century, which are still partially active in the city. 

SMAS has introduced chemical water treatment, which has improved the quality of the “Company's water,” which was previously only filtered.