Sewage treatment plants in Inca,
for the houses of the Pla.

It needs one of the three solutions the Balearic Water Plan allows (Royal Decree 49/2023, art. 70.1): an on-site treatment system, a sealed holding tank or a natural treatment system with a favourable report. An old cesspit is none of the three. In Inca's country houses the usual choice is an extended-aeration plant, with the minimum performance the rules require (BOD₅ 70%, COD 75%, suspended solids 70%) proven by the manufacturer under EN 12566-3.

Decree 18/2023 puts 56.5 km² of Inca in the zone vulnerable to farm nitrates. That rule governs fertilising fields, not your treatment plant, but it says the aquifer below is already loaded. What changes the unit is your plot's vulnerability on the Water Plan map: where it is high, only a green area is allowed, and the Plan also lists denitrification and disinfection, recommended up to 12 population equivalents and required above 12 (art. 70.10, tables 13 and 14). We check it before quoting.

Inside the municipality of Inca the Water Plan's wetland catalogue lists none; the nearest is Son Llampaies, in Selva, between Inca and Lloseta. The 500 m distance only counts for houses of 12 population equivalents or more, so for an ordinary home it changes nothing. For a large house or agritourism towards Lloseta, we measure it first.

25 m² of green area per population equivalent, and in a home the Plan's guideline equivalence is one per bed space (art. 70.8 and 70.12 of the Balearic Water Plan): 100 m² for a 4-bed-space house, 200 m² for an 8. With that, a responsible declaration to Recursos Hídrics is enough. Without it, the options are a drainage trench with prior authorisation or a sealed holding tank.

Almost always it is the Direcció General de Recursos Hídrics asking, as part of the responsible declaration: proof of purchase and installation, technical specifications, the manufacturer's performance data and a maintenance plan (art. 70.4 of the Water Plan). We prepare and sign it as the installation company, and your architect or technical adviser files it.

Service visits are the ones the regulations require or, if the manufacturer asks for more, the manufacturer's: on the GRAF one2clean, for example, two a year. Sludge emptying is done by an authorised waste-management company, as the law requires (art. 70.7.f), whenever the manufacturer says; on the one2clean the settling test at the service decides it. Keep the receipts for the last five years.