Sewage treatment plants in Mallorca
Septic tank, treatment plant or holding tank, the documents and maintenance, in detail.
See the guide →Treatment plants · Algaida
Sewage treatment plants in Algaida: the Pla municipality with the most homes off the network
In Algaida, 2,492 of its 6,421 residents live in scattered homes, according to INE's 2025 Nomenclátor: almost four in ten, between Algaida, Pina and Randa. They are country houses the mains sewer does not reach, and each one needs its own system. We are Joaquín and Juan, installers in Mallorca since 1998: we supply the new treatment plant, 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
- Homes on rural land
- Since 1998
GRAF one2clean · Image: GRAF
Your area
What the Water Plan says about Algaida's water
Annex 9 of the Water Plan describes the Montuïri groundwater body (1815M2), shared by Montuïri, Algaida, Porreres and Sant Joan: 83 km² of small aquifers, with no contact with the sea.
Water with salts, from natural causes
That body has 330 mg/l of chlorides and 220 mg/l of sulphates. The Plan attributes it to the marly materials of the Middle Miocene, the Pina marls, and for that reason takes it as given that it will never reach good status. For a house: well water in the area can come out laden with salts, and that counts for irrigation and for the house.
The Algaida and Montuïri treatment works
The Montuïri-Algaida public treatment works discharges about 0.26 hm³ a year over this body, and its remodelling is in the Plan's programme of measures. It serves the villages; the country houses are left out.
Nitrate-vulnerable zone
Decree 18/2023 declares 29.8 km² of the municipality of Algaida, around a third, a vulnerable zone, over the Algaida body (1815M3). Whether your plot is there or not, and how vulnerable the aquifer is, we check on the DGRH map.
Sources: Balearic Water Plan, Royal Decree 49/2023 (regulations, art. 70, 71, 76 and 77) · Annex 9 of the Plan, entries for the groundwater body “Montuïri (1815M2)” · EN 12566 · manufacturer's manual (GRAF one2clean, as an example).
The rules here
Large fincas, agritourism and houses that grow
The treatment plant is sized by population equivalents: in a home, rural house or agritourism, one per bed space (art. 70.8 and table 12 of the Water Plan, Royal Decree 49/2023). Above 12, the pre-treatment includes grease removal and every year the performance check and the sludge log are sent to the Balearic Directorate-General for Water Resources (art. 70.11).
If you extend the house and add bedrooms, it has to be checked that the unit covers the new bed spaces. And in hospitality, agritourism included, the grease separator before the treatment plant is compulsory (art. 70.7.e).
What we do
What we do in Algaida, and what others do
- A plant sized by bed spaces, one population equivalent per bed space in a home or agritourism property (art. 70.8), approved with CE marking under EN 12566 (art. 70.14) and, above 12, with grease removal. We work with all brands; as an example, the GRAF one2clean.
- The complete installation, in Algaida, Pina or Randa: installation, the blower's power line as an authorised low-voltage installation company and commissioning; in hospitality, also the grease separator required by art. 70.7.e. We don't subcontract anyone.
- Digging in marl ground: your builder does it, and may hit rock or clay, with our written instructions according to the manufacturer. Treated water is better sent to a garden area than to a trench; the sludge goes to an authorised waste company (art. 70.7.f).
- The documents for the responsible declaration, prepared and signed as the installation company; your architect or engineer files them. For an agritourism property with more than 12 bed spaces, we explain the annual submission of monitoring and the sludge log (art. 70.11).
- Services with a signed report: those required by the rules or, if the manufacturer asks for more, the manufacturer's (on the GRAF one2clean, twice a year). And if you extend the house, we check the unit covers the new bedrooms.
How we work
How we do it in Algaida, in 3 steps
1
Algaida, Pina or Randa?
Tell us the village, the location, the maximum bed spaces and where the water will go, with photos of the ground. We check on the DGRH map whether the plot falls in the municipality's vulnerable zone.
2
Counting bed spaces, and the quote
We add up bed spaces and, in agritourism, staff, to size the unit and the 25 m² of garden area per population equivalent. You get it in writing with installation, electrics and documents.
3
Installation on site
Once your builder has dug the pit, we install, connect the blower and start the unit. We hand the signed documents to your engineer to file.
Keep learning
More on treatment plants and energy in Algaida
The general guide to treatment plants and what else we do in your area.
Solar panels in Algaida
Self-consumption for the house, the treatment plant blower included.
See solar in Algaida →Heat pumps in Algaida
Heating and hot water with a heat pump.
See heat pumps in Algaida →Across Mallorca
Sewage treatment plants in the Pla de Mallorca: Petra · Sineu · Llubí · Porreres, or see the guide to sewage treatment plants in Mallorca →
Need the house drainage (downpipes, rainwater, chambers)? Drainage in Mallorca →
Sewage treatment plants near Algaida: Llucmajor · Palma
Also in Algaida: air conditioning
See our work and customer reviews on the JSL Google Maps profile →
Common questions
Frequently asked questions about treatment plants in Algaida
How many houses in Algaida are off the mains sewer?
There is no census of houses, but there is one of people: according to INE's 2025 Nomenclátor, 2,492 of Algaida's 6,421 residents live in scattered homes (2,298 in Algaida, 160 in Pina and 34 in Randa). A house with no access to the network needs an on-site treatment system, a sealed holding tank or a natural system with a favourable report (art. 70.1 of the Balearic Water Plan).
My country house is near Pina: is there anything special about the ground?
The Water Plan names the Pina marls, marly materials of the Middle Miocene, as the source of the chlorides (330 mg/l) and sulphates (220 mg/l) of the Montuïri body. In marly ground water infiltrates poorly: one more reason to reuse the treated water irrigating a green area (art. 70.12) and not to rely on a trench, which also needs prior authorisation.
I have an agritourism property with 14 bed spaces in Algaida: what applies to me?
In agritourism one population equivalent is counted per bed space, plus the staff (table 12 of the Balearic Water Plan, Royal Decree 49/2023). With more than 12, the pre-treatment includes grease removal and every year the performance check and the sludge log are sent to the DGRH (art. 70.11). In hospitality, moreover, the grease separator is compulsory (art. 70.7.e).
I'm going to extend the house in Randa with two bedrooms: will the treatment plant I have do?
It has to be checked that it covers the new bed spaces: in a home one population equivalent is counted per bed space (art. 70.8 of the Balearic Water Plan, Royal Decree 49/2023) and the plant is sized for the maximum number of people. The green area too: 25 m² for each of them. If the house is under construction, the prior notification goes first and then there are two years for the declaration (art. 70.5).
Who does the excavation?
Your builder: the pit, the sand bed and backfill, the trenches and the inspection chambers. Before they dig we give them in writing how it has to be according to the manufacturer, because a badly bedded tank loses its warranty. In the municipality of Algaida the Water Plan (Royal Decree 49/2023) describes carbonate materials and marls: rock or clay may come up.
What happens if the mains sewer arrives in the future?
Until the connection is effective, the house must have one of the systems of art. 70.1, and once the network is working there is one year at most to connect (art. 70.9 of the Balearic Water Plan, Royal Decree 49/2023). For Algaida, Annex 9 of the Plan includes the remodelling of the Algaida-Montuïri treatment works; about extending the network to rural land it says nothing.
Quality
We work with all brands
As an example, GRAF tanks. We propose the unit for each house and what the area requires.
A country house in Algaida, Pina or Randa with no mains sewer?
Send us the location, the bed spaces, where the water will go and a few photos of the ground. We reply within 24-48 hours on working days.