Sewage treatment plants in Mallorca
Septic tank, treatment plant or holding tank, the documents and maintenance, in detail.
See the guide →Treatment plants · Selva
Sewage treatment plants in Selva, upstream of s'Albufera
What leaves a finca in Selva or in Caimari ends up, down the torrent, in the sa Pobla aquifer and in s'Albufera. That is why treating the water properly matters here. We are Joaquín and Juan, installers in Mallorca since 1998: we supply the new treatment plant for fincas, country houses and rural guesthouses with no mains sewer, install it, do the electrics and prepare and sign the documents for your architect or engineer to file.
Send us photos and details · Reply within 24-48 hours on working days · We assist you in English, Spanish and German
- New approved unit
- Signed documents
- Rural guesthouses and agroturismos
- Since 1998
Your area
Where the water from Selva goes
Selva lies at the head of a catchment that the Balearic Water Plan describes in two data sheets of its Annex 9: one for a torrent and one for an aquifer. And one in four residents of the municipality, 1,062 out of 4,313 according to the INE's 2025 gazetteer, lives scattered across the countryside, outside the villages.
The Sant Miquel torrent
The catchment of the Búger-Sant Miquel torrent (11017309), of 145 km², drains this side of the Serra de Tramuntana towards s'Albufera de Mallorca, in sa Pobla. It receives the water from four treatment works, among them Selva's (0.16 hm³ a year), and its status is poor, with high phosphates. The Plan provides for enlarging and improving the Selva treatment works, and records the Moscari sewers as built.
The sa Pobla aquifer
Part of the municipality lies over the sa Pobla groundwater body (1811M1), of 130.5 km², in poor status: 140 mg/l of nitrates, almost three times the limit, and 107% abstraction. It has had nitrate vulnerable zone programmes since 2000.
Fincas in the mountains
Towards Caimari and Binibona, the fincas climb up terraces, with rock near the surface and little flat ground. There we study where the green irrigation area fits, 25 m² per population equivalent (art. 70.12), and how the pit is dug.
Sources: Balearic Water Plan, Royal Decree 49/2023 (regulations, art. 70 and 71) · Annex 9 of the Plan, data sheets for the groundwater body “sa Pobla (1811M1)” and the surface water body “Búger-Sant Miquel (11017309)” · EN 12566 · manufacturer's manual (GRAF one2clean, as an example).
The rules here
Rural guesthouses and agroturismos: how it is counted
The treatment plant is sized in population equivalents. Table 12 of the Water Plan gives the equivalences: in a home, rural guesthouse or agroturismo, one per bed space; workers who live on the finca, one each, and those who don't, a quarter; in restaurants and event venues, a quarter per seat.
In hospitality, agroturismo included, a grease separator before the treatment plant is compulsory (art. 70.7.e). And above 12 population equivalents (not with exactly 12), the performance check and the sludge log are sent every year to the Balearic water authority (Direcció General de Recursos Hídrics) (art. 70.11).
What we do
What we do in Selva, and what others do
- Counting the bed spaces properly: in a rural house or agritourism, one population equivalent per bed space, plus the staff (table 12 of the Plan). With that figure we choose a new approved treatment plant, CE marked and EN 12566 (art. 70.14). All brands; for example, the GRAF one2clean.
- Installation on terraces, below the house so the water flows by gravity, with the electrics and commissioning done as a licensed low-voltage installation company. In hospitality, with its grease separator (art. 70.7.e). We don't subcontract anyone.
- The pit and the sludge: towards Caimari and Binibona the rock is close to the surface. Your builder digs following what we give them in writing according to the manufacturer, leaving access for the authorised waste company's truck that empties the sludge (art. 70.7.f).
- The documents: the responsible declaration always and, above 12 population equivalents, the yearly submission of the performance check and the sludge log (art. 70.11). We prepare and sign as the installation company; your architect or engineer files them.
- The services required by the rules or, if the manufacturer asks for more, the manufacturer's (on the GRAF one2clean, twice a year), with a signed report, also if the rural house closes in winter: whatever leaves here flows down towards s'Albufera.
How we work
How we do it in Selva, in 3 steps
1
Bed spaces, staff and meals
Location, bed spaces, whether there is staff or meals are served, where the water will go and photos. With that we work out the population equivalents and look at your estate on the DGRH map viewer.
2
A written quote for your estate
Unit, grease separator if there is hospitality, installation, electrics and documents. Your builder gets in writing the dimensions of the pit on the terrace.
3
Installation, start-up and documents
We install once the pit is dug, commission the plant and give your engineer the signed documents. The treated water irrigates 25 m² per population equivalent (art. 70.12).
Keep learning
More on treatment plants and energy in Selva
The general guide to treatment plants and what else we do in your area.
Solar panels in Selva
Self-consumption for the house, the treatment plant blower included.
See solar in Selva →Heat pumps in Selva
Heating and hot water with a heat pump.
See heat pumps in Selva →Across Mallorca
Sewage treatment plants in the Raiguer and the Tramuntana: Alaró · Consell · Sencelles · Bunyola · Esporles, or see the guide to sewage treatment plants in Mallorca →
And for the summer: air conditioning in Selva →
Need the house drainage (downpipes, rainwater, chambers)? Drainage in Mallorca →
Sewage treatment plants near Selva: Campanet · Inca · Lloseta
See our work and customer reviews on the JSL Google Maps profile →
Common questions
Frequently asked questions about treatment plants in Selva
I have an agroturismo in Binibona with 14 bed spaces: which treatment plant does it need?
One calculated for a little over 14 population equivalents: according to table 12 of the Balearic Water Plan (Royal Decree 49/2023) you count one per bed space, plus the workers (one if they live on the finca, a quarter if not). Above 12, the pre-treatment includes grease removal, the grease separator is compulsory in hospitality (art. 70.7.e) and the check is sent to the DGRH every year (art. 70.11).
Why does treating the water properly matter so much in Selva?
Because the water runs down towards s'Albufera. According to Annex 9 of the Water Plan (Royal Decree 49/2023), the catchment of the Búger-Sant Miquel torrent is in poor status, and the sa Pobla aquifer, which reaches as far as Selva, has 140 mg/l of nitrates, when the limit for good status is 50 mg/l. A house that treats its water and irrigates its own plot does not add to that problem.
My house is in Moscari: is there a mains sewer?
The Water Plan records the sewers and pumping stations of Moscari as built, and the village is listed among those that send their water to the Selva treatment works. What counts is your plot: if it is a country house, on rural land and with no access to the network, it needs its own system (art. 70.1 of the Balearic Water Plan, Royal Decree 49/2023). We confirm it with Selva town hall.
On a terraced finca, where does the treatment plant go?
Below the house, so that the water arrives by gravity, and somewhere a lorry can get close to empty the sludge, which is a job for an authorised waste company (art. 70.7.f). The excavation is done by your builder; beforehand we give them in writing the dimensions of the pit according to the manufacturer. The treated water irrigates a green area of 25 m² per population equivalent (art. 70.12). On the fincas of Caimari and Binibona it is the first thing we look at.
What maintenance does the treatment plant of a rural guesthouse need?
The servicing the regulations set or, if the manufacturer asks for more, the manufacturer's: on the GRAF one2clean, as an example, two a year, with a signed report. Above 12 population equivalents, the performance check is also sent to the DGRH every year (art. 70.11). If the house closes in winter, the treatment plant is left with the power on.
Which unit do you install in Selva?
A new treatment plant, approved, with CE marking and compliant with EN 12566 (art. 70.14 of the Water Plan), achieving at least 70% for BOD₅, 75% for COD and 70% for suspended solids (art. 70.10). We work with every brand; as an example, the GRAF one2clean. The model depends on the bed spaces and on how the house is used. On a finca in Selva or Caimari we also check what the sa Pobla aquifer requires.
Quality
We work with all brands
As an example, GRAF tanks. We propose the unit for each house and what the area requires.
A finca or rural guesthouse in Selva with no mains sewer?
Send us the location, the bed spaces, whether there are workers or meals served, and a few photos. We reply within 24-48 hours on working days.