In just a few minutes and without any paperwork, this tribunal settles irrigation conflicts that erupt in the fertile plain that surrounds Valencia, Spain's third largest city, a Mediterranean region of orchards.
UN cultural body UNESCO has included the court -- which bills itself as "the oldest institution of justice in existence in Europe" -- on its list celebrating the world's "intangible cultural heritage" which deserves protection.
The tribunal's existence dates back at least to the 10th century when this region was ruled by Muslims and the Gothic cathedral where the tribunal meets today was a mosque.
It deals with cases of stolen water, a precious resource in drought-prone Spain, or disagreements over the interpretation of rules managing the irrigation system.
Disputes can happen at any time of the year but they are more frequent during droughts when special rules governing irrigation are imposed and "supervision is enforced to control the availability of water," said historian Daniel Sala, an expert on the Water Court.
One recent case was brought forward by Vicent Marti, who has operated an ecological farm for over 30 years.
He turned to the tribunal after noticing that the water arriving at his farm was polluted with traces of cement and paint thrown into the irrigation system by workers renovating a neighbour's house.
After hearing both sides, and a brief debate among the tribunal members, the president of the court announced that Marti's neighbour was at fault.
Following tradition, he indicated his acceptance of the ruling by saying "correct" and was later fined 2,000 euros ($2,285).
"I felt bad reporting it because we are neighbours, but I did not have much choice," Marti told AFP.
His farm produces ecological produce, which is subject to strict quality controls, and the "survival" of his business was at stake, he added.
The court in its current form is made up of eight members, all of them men, who are elected by the roughly 10,000 farmers who use the irrigation system set up in the plains around Valencia.
Each member of the tribunal represents one of Valencia's eight communities of irrigators, known as "acequias", which grow vegetables and tubers, such as tiger nuts that are pounded to make horchata, a popular Spanish drink.
The court meets every Thursday at noon outside the Door of the Apostles of Valencia's cathedral, which houses a gold chalice said to be the one used by Jesus at the Last Supper.
The proceedings, which are watched by a crowd of locals and tourists, are carried out in Valencian, the local language.
All decisions are final and cannot be appealed. The tribunal's rulings "have been respected by dictators, presidents, kings, everybody," said Sala.
Preventing a fossilised institution
Two factors are threatening farming on the plains of Valencia -- and by extension the survival of the tribunal: the reduction in the amount of land that is farmed due to urbanisation and the ageing of the population.
Enrique Navarro, a 44-year-old farmer, criticises the fact that the majority of tribunal members are over the age of 60.
He says a "generational renewal" is needed so that the court "does not end up becoming a fossilised institution."
Of the hundreds of water disputes that arise each year, just 20-25 actually reach the tribunal. On some Thursdays no one appears at the door of the cathedral with a case.
The crowds, which turn out to watch the proceedings held in the historic centre of Valencia, also dissuade many farmers from bringing forward a case.
"For a labourer it is almost an offence to come here," said Jose Antonio Monzo, who enforces irrigation rules at a community of irrigators called Quart.
Enrique Aguilar, the vice president of the tribunal, said that 90 percent of all disputes are solved through mediation, sometimes just a few minutes before the tribunal's weekly session.
"We try to make it so nobody makes it here," he said, in front of the cathedral door where the tribunal meets.
And sometimes just the prospect of being brought before the tribunal can be enough to settle a dispute.
"Out in the fields, the accused is proud, claims he is not at fault. But when he presents himself here, he asks for mediation," added Manuel Ruiz, the president of the tribunal.