Sewage treatment plants in Mallorca
Septic tank, treatment plant or holding tank, the documents and maintenance, in detail.
See the guide →Treatment plants · Sineu
Sewage treatment plants in Sineu: a whole municipality on a vulnerable zone
In Sineu, 740 of its 4,552 residents live in country houses outside the village (INE, Nomenclátor 2025), with no mains sewer to connect to. And the Decree on nitrate-vulnerable zones includes 47.7 km² of Sineu: the size of the municipality. We are Joaquín and Juan, installers in Mallorca since 1998: we supply the new treatment plant, with its installation, its electrics and the documents prepared and signed for your architect or engineer to file.
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- New approved unit
- Signed documents
- Aquifer and wells checked
- Since 1998
GRAF one2clean · Image: GRAF
Your area
Sineu, where three aquifers meet
The municipality of Sineu appears in three entries of Annex 9 of the Water Plan: the Petra, Llubí and Ariany groundwater bodies. All three are in poor chemical status because of nitrates.
Under the village: the Petra body
The village of Sineu lies over the Petra body (1815M4), with 98 mg/l of nitrates on average and an abstraction index of 99%. It is a set of small aquifers of carbonate and detrital materials, with alluvial deposits on top.
To the north: Llubí and Ariany
The Llubí body (1811M2) has 54 mg/l of nitrates and the Ariany body (1816M1), 72. Into the latter discharges the public treatment works that Sineu shares with Petra, Maria de la Salut and Ariany (0.51 hm³ a year), whose remodelling is in the Plan's programme of measures.
What it means for your house
Decree 18/2023 declares 47.7 km² of Sineu a nitrate-vulnerable zone. For a country house, the practical point is that the treated water should go to a green area on the plot and that, before choosing a unit, the vulnerability of the aquifer at that spot is checked.
Sources: Balearic Water Plan, Royal Decree 49/2023 (regulations, art. 70, 71, 76 and 77) · Annex 9 of the Plan, entries for the groundwater bodies “Petra (1815M4)”, “Llubí (1811M2)” and “Ariany (1816M1)” · EN 12566 · manufacturer's manual (GRAF one2clean, as an example).
The rules here
Responsible declaration or prior authorisation
The responsible declaration to the Balearic Directorate-General for Water Resources is enough when the treated water is reused on your green area: 25 m² per population equivalent (art. 70.12 of the Water Plan, Royal Decree 49/2023). A prior authorisation is needed if it goes to an infiltration trench or soakaway, whatever the number of bed spaces, or with 12 population equivalents or more inside the well restriction perimeter or 500 m or less from a wetland.
As the installation company we prepare and sign the documents your architect or engineer asks for: the declaration that the installation complies with the rules, the manufacturer's performance, the maintenance plan and the electrical certificate. Your architect or engineer files them.
What we do
What we do in Sineu, and what others do
- The documents depend on where the water goes: if it waters your garden area, a responsible declaration; if it goes to a trench or soakaway, prior authorisation. We prepare and sign them as the installation company, and your architect or engineer files them.
- A new extended-aeration treatment plant in place of the old septic tank, approved with CE marking and EN 12566 (art. 70.14) and with the performance required by art. 70.10. We work with all brands; as an example, the GRAF one2clean.
- The supply line and a sealed outdoor sub-panel for the blower, which pumps in air 24 hours a day, as an authorised low-voltage installation company and with its certificate; plus installation and commissioning. We don't subcontract anyone.
- For the pit, your builder gets the manufacturer's requirements in writing; before that, you will have told us which wells are near your house in Sineu and how far away. Sludge emptying is done by an authorised waste company (art. 70.7.f).
- Services and maintenance: those 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 after every visit.
How we work
How we do it in Sineu, in 3 steps
1
Location and nearby wells
Tell us where the house is, how many bed spaces it has and which wells are nearby. We check which of the three water bodies it sits on, Petra, Llubí or Ariany, and its vulnerability on the DGRH map.
2
Garden or trench, and the quote
We work out the garden area you have: a house with 6 bed spaces needs 150 m². That tells us which procedure applies, and we send you the quote in writing.
3
Works, power and folder
With the pit dug, we install the plant, run the blower's power line and commission it. We hand your engineer the signed documents to file.
Keep learning
More on treatment plants and energy in Sineu
The general guide to treatment plants and what else we do in your area.
Solar panels in Sineu
Self-consumption for the house, the treatment plant blower included.
See solar in Sineu →Heat pumps in Sineu
Heating and hot water with a heat pump.
See heat pumps in Sineu →Across Mallorca
Sewage treatment plants in the Pla de Mallorca: Petra · Llubí · Algaida · 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 Sineu: Muro · Inca
Also in Sineu: air conditioning
See our work and customer reviews on the JSL Google Maps profile →
Common questions
Frequently asked questions about treatment plants in Sineu
Is all of Sineu a nitrate-vulnerable zone?
Practically. The Balearic Government's Decree 18/2023 (BOIB no. 39 of 28-3-2023) includes 47.7 km² of the municipality of Sineu, which is its whole area. The three groundwater bodies it touches —Petra, Llubí and Ariany— are in poor status because of nitrates according to Annex 9 of the Water Plan: 98, 54 and 72 mg/l.
Does that oblige me to fit a special treatment plant in my Sineu house?
Not by itself. The vulnerable zone regulates agricultural fertilising. What changes the unit is your plot being in a high-vulnerability zone of the aquifer or inside the perimeter of a public supply well: then the treatment plant includes denitrification and disinfection (art. 70.10, table 13 of the Balearic Water Plan). We check it on the DGRH map with your location.
I have an old septic tank on the finca: will it do?
A septic tank only settles. The Balearic Water Plan requires a minimum performance of BOD₅ 70%, COD 75% and suspended solids 70% (art. 70.10), certified by the manufacturer under EN 12566-3, and a cesspit is none of the solutions of art. 70.1. In Sineu, over aquifers with 54 to 98 mg/l of nitrates, what we install is a new total-oxidation treatment plant.
How much green area do I need for the treated water?
At least 25 m² per population equivalent (art. 70.12 of the Balearic Water Plan, Royal Decree 49/2023), and in a home one is counted per bed space (art. 70.8): a house with 6 bed spaces in Sineu needs 150 m². If you don't have them, what remains is the sealed holding tank emptied periodically or the drainage trench, which needs a favourable report and prior authorisation.
Is the mains sewer going to reach the country houses of Sineu?
What Annex 9 of the Water Plan includes for these aquifers is the remodelling of the public treatment works of Sineu, Petra, Maria de la Salut and Ariany; it says nothing about a network for rural land. And even if it did arrive, until the connection is effective the house must have one of the systems of art. 70.1 (art. 70.9 of the Balearic Water Plan).
Does the treatment plant need electricity?
Yes: a blower pumps air 24 hours a day so the bacteria can work. As an authorised low-voltage electrical installer we run the line and a sealed outdoor sub-board next to the treatment plant, and hand over the electrical installation certificate. In a country house in Sineu with solar panels, the blower is a small, constant load that the panels cover in the daytime.
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 Sineu with no mains sewer?
Send us the location, the bed spaces, which wells are nearby and a few photos. We reply within 24-48 hours on working days.