Sewage treatment plants in Mallorca
The full guide: septic tank or treatment plant, paperwork, treated water and maintenance.
See the guide →Sewage treatment · Cala Millor
Sewage treatment plants in Cala Millor and its countryside, between Son Servera and Sant Llorenç
Cala Millor is split between two municipalities: the north part belongs to Son Servera and the south to Sant Llorenç des Cardassar. The settlements have a sewer, but the countryside around does not: the Sant Llorenç sewerage regulation asks houses on rustic land to have their own system. We are Joaquín and Juan, installers in Mallorca since 1998: we supply the new treatment plant, fit it, leave it running and prepare and sign the documents your architect or engineer asks for.
Send us photos and details · Reply within 24-48 hours on working days · We assist you in English, Spanish and German
- Fincas in Son Servera and Sant Llorenç
- New approved unit
- Signed documents
- Since 1998
Image: GRAF
Your area
Cala Millor: two municipalities, two ways of looking at your house
The underlying rules are the same across the island: the Balearic Islands Water Plan (Royal Decree 49/2023, art. 70). What changes in Cala Millor is which municipality your house is in and what lies underneath.
The Son Servera side
According to the layer of settlements served by ABAQUA published by the Balearic government (IDEIB viewer), the Son Servera treatment plant serves Cala Millor, Cala Bona, the village of Son Servera and Costa des Pins. Houses in the municipality that are outside those settlements or beyond their network treat the water on their plot, with an approved unit.
The Sant Llorenç side: what its regulation says
The Sant Llorenç des Cardassar sewerage regulation (BOIB no. 159, 7 December 2024) is very clear. If the public network is less than 100 metres away and can be reached along public roads, connecting is compulsory (art. 9.2). On rustic land, the house must have a stand-alone treatment system, a sealed holding tank or natural treatment, as art. 70 of the Water Plan sets out (art. 9.3). And the trucks that empty septic tanks may only unload at the sa Coma treatment plant (art. 29).
Vulnerable aquifer and protected areas
Cala Millor sits on the "Portocristo" groundwater body (1820M3) and the village of Sant Llorenç on the "Sant Llorenç" body (1817M3), both nitrate vulnerable zones (Decree 18/2023), and on the Balearic government's aquifer vulnerability map Cala Millor shows as high vulnerability, where treated water may only go to a green area, with denitrification and disinfection (art. 70.10, table 13). To the south, Punta de n'Amer is an Area of Natural Interest (ANEI) and, past sa Coma, the Riuet de s'Illot is a catalogued wetland (MAZH12): within 500 m, if the house may significantly affect it, a favourable report is needed (art. 77.3).
What we do
What we do in Cala Millor, plainly
- The new extended-aeration treatment plant (or the holding tank, when that is the right answer): approved, CE-marked and from the EN 12566 family, as the Water Plan requires (art. 70.14). We work with every brand; as an example, the GRAF one2clean.
- Installation, electrics and commissioning: the electrics as an authorised low-voltage installation company.
- The documents: we prepare and sign them as the installation company, and your architect or engineer files them.
- Digging the pit is done by your builder, and beforehand we give them in writing how it must be left according to the manufacturer. Sludge emptying is done by an authorised waste management company, as the law requires (art. 70.7.f).
- Service visits on what we install: the ones the regulations require or, if the manufacturer asks for more, the manufacturer's (two a year on the GRAF one2clean). We don't subcontract anyone.
The paperwork
Which paper applies to a house in Cala Millor
Once the unit is installed and the water irrigates the plot, the responsible declaration to the Direcció General de Recursos Hídrics (DGRH), which is always filed (art. 70.4); in Sant Llorenç the municipal regulation also mentions it. For a house under construction, the prior notice goes to Recursos Hídrics first, and from then two years at most for the declaration (art. 70.5). If the water goes to a drainage trench, a favourable report and an authorisation as well (art. 70.12).
What art. 70.4 asks you to attach (unit specifications, performance according to the manufacturer, maintenance plan and proof of purchase and installation) we prepare and sign ourselves, together with the certificate for the power line; your architect or engineer files it with Recursos Hídrics.
Sources: Balearic Islands Water Plan, RD 49/2023 (art. 70) · wetland catalogue, supply boreholes and aquifer vulnerability in the Balearic government IDEIB viewer · Sant Llorenç des Cardassar sewerage regulation, BOIB no. 159, 7 December 2024 · nitrate vulnerable zones (Decree 18/2023).
How we work
How we do it in Cala Millor
1
You send us the details
Location, maximum beds, how the house is used, where the water will go, what is nearby, photos and your email.
2
We check and quote
We check wetlands, wells and aquifer vulnerability, and send you a written quote.
3
Installation and documents
We fit the plant once the pit matches what we gave you in writing, commission it and hand over the signed documents.
Keep learning
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See solar in Cala Millor →Heat pumps in Cala Millor
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See heat pumps in Cala Millor →Other areas off the mains
Sewage treatment plants in other areas with homes off the mains: Valldemossa · ses Salines, or see the guide to sewage treatment plants in Mallorca →
Sewage treatment plants near Cala Millor: Manacor · Porto Cristo · Cala Ratjada
Also in Cala Millor: air conditioning · water softeners
See our work and customer reviews on the JSL Google Maps profile →
Common questions
Frequently asked questions about sewage treatment plants in Cala Millor
Is my house in Cala Millor in Son Servera or in Sant Llorenç?
It depends on the street: Cala Millor is split between the two municipalities, the north in Son Servera and the south in Sant Llorenç des Cardassar. We check it with the Google Maps location on the Balearic government's official municipal map, because it changes which regulation applies and which town hall issues the licence.
My finca in Sant Llorenç is near the sewer, can I still fit a treatment plant?
If the public network is less than 100 metres from the house and the connection is feasible along public roads, the Sant Llorenç regulation makes connecting compulsory, at the owner's cost (art. 9.2). If it is further away or on rustic land, you need your own system: a treatment plant, a sealed holding tank or natural treatment (art. 9.3).
Where is the sludge from the treatment plant emptied?
It is removed by an authorised waste management company with a tanker truck (art. 70.7.f of the Water Plan). In Sant Llorenç the municipal regulation sets that this truck may only unload at the sa Coma treatment works (art. 29). That is why we leave the tank opening reachable from the track.
Can I irrigate the garden with the treated water?
Yes, and it is what we recommend: the rules ask for 25 m² of green area per population equivalent (art. 70.12), 100 m² for a 4-bed house. Also, Cala Millor and the Sant Llorenç countryside lie on aquifers declared nitrate vulnerable, so irrigating is a better destination than infiltrating.
Does power have to be brought to the treatment plant?
Yes. An extended aeration treatment plant has a blower that moves air 24 hours a day. We run the line from the house consumer unit to a sealed outdoor sub-board next to its cabinet, as an authorised low-voltage installation company. If the holiday home is closed in winter, the blower keeps running so the biology is not lost.
Do you cover Cala Millor, Cala Bona and the countryside around?
Yes: Cala Millor, Cala Bona, Costa des Pins, sa Coma and the fincas in Son Servera and Sant Llorenç. We reply within 24-48 hours on working days, in English, Spanish or German. Servicing follows what the rules set or, if the manufacturer asks for more, the manufacturer's (two a year on the GRAF one2clean). We don't subcontract anyone.
Quality
We work with every brand
As an example, GRAF tanks. We propose the unit according to the beds and the use of each house.
A house in Cala Millor or its countryside with no sewer?
Send us the location, the maximum number of occupants and photos of the drain outlet and the access, and tell us whether the house is in Son Servera or Sant Llorenç, if you know. We reply within 24-48 hours on working days.