Sewage treatment · Mallorca
Sewage treatment plants in Mallorca: new, installed and documented
If your house has no mains sewer, the water leaving it is your responsibility, and the Balearic water authority now asks for documents nobody asked for ten years ago. We are Joaquín and Juan, installers in Mallorca since 1998. We fit new treatment plants: the approved unit, the installation, the electrics, the commissioning and the documents your architect asks for, prepared and signed. Here is what we do, how the work is shared out, what the rules say and what to send us for a quick quote.
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- New approved unit
- Signed documents
- Service visits as the manufacturer requires
- Since 1998
What we do, said clearly from the start
So you know from day one what to count on. We fit new treatment plants: we supply the unit ourselves, install it and stand behind it.
What we do
- A new extended-aeration treatment plant (or a sealed holding tank, when that is what fits): approved, CE-marked and compliant with the EN 12566 family, as the Balearic Water Plan requires (art. 70.14). We work with all brands; as an example, the GRAF one2clean.
- Installation and connections: inlet from the house, outlet for the treated water, ventilation and air hoses up to the blower cabinet.
- The electrics: a supply line and a weatherproof outdoor sub-panel next to the cabinet, as an authorised low-voltage installation company, so nobody has to go into the house to reset anything.
- Commissioning, and we explain what you need to check between service visits.
- The documents: as the installation company we prepare and sign the documents Recursos Hídrics asks for (technical specifications, the manufacturer's performance data, the maintenance plan and proof of purchase and installation) and hand them over for your architect or technical adviser to file.
- Upkeep of what we install: the service visits the regulations require or, if the manufacturer asks for more, the manufacturer's (two a year on the GRAF one2clean), with a signed report.
What others take care of, and how we coordinate it
- Digging the pit. The digging, the sand bed and backfill, the trenches and the inspection chambers are done by your builder. Before anyone digs, we give you in writing how the pit must be left according to the manufacturer.
- Filing the documents with Recursos Hídrics or the town hall. We hand over the documents prepared and signed, and your architect or technical adviser files them.
- Sludge emptying. An authorised waste-management company does it, as the law requires (art. 70.7.f of the Balearic Water Plan).
For a quick quote, send us this
With these details we can almost always quote without a site visit, and we reply within 24-48 hours on working days. If anything is missing, we'll ask.
- Where the house is: the municipality and, if you can, the Google Maps location.
- How many bed spaces it has at most. The Water Plan gives 1 population equivalent per bed space in a home as a guideline equivalence (art. 70.8, table 12) and asks for the capacity to be justified by use and occupancy. We size the plant for the maximum, not the average: if you are 10 in summer, it is a 10.
- Main home or holiday home. In a house that stands empty for weeks the bacteria still need feeding, and that changes the unit.
- Where the treated water will go: garden irrigation on your plot, a soakaway trench or a soakaway pit. And how many square metres of garden you have.
- What is nearby: wells (yours, the neighbours' or the town's water supply) and wetlands, and how far away they are.
- Photos of where the drain leaves the house, of the spot where the tank would go and of whatever is there now (an old cesspit or septic tank).
- If there is an architect or a project, the drawings in DXF or DWG and the bill of quantities in BC3.
- Your email address, so we can send you the quote and, later, the documents.
Septic tank, treatment plant or holding tank: what the rules allow
The Balearic Water Plan (Royal Decree 49/2023, art. 70.1) only allows three solutions for a house with no mains sewer: an on-site treatment system, a sealed holding tank that is emptied periodically, or a natural treatment system with a favourable report from the water authority. The old-style cesspit is none of the three.
A septic tank only separates: the solids stay behind and the water leaves almost as dirty as it came in. An extended-aeration treatment plant blows air in through a blower and diffusers, and bacteria break down the organic load. The rules require a minimum performance of BOD₅ 70%, COD 75% and suspended solids 70% (art. 70.10), and the manufacturer proves it with its EN 12566-3 test. That is why what we install is a treatment plant.
A sealed holding tank is for when there is no ground for the treated water, or for occasionally used houses where treatment is not practical (art. 70.2). It discharges nothing, but it has to be emptied completely every time it fills. If there is ground available, a treatment plant almost always works out cheaper to run.
The documents: what is always filed, when an authorisation is needed and who files it
- Always: a responsible declaration (declaración responsable) to the Direcció General de Recursos Hídrics (DGRH) once the unit is installed, also below 12 population equivalents. It carries four documents: proof of purchase and installation, technical specifications, performance and a maintenance plan (art. 70.4 of the Balearic Water Plan).
- If it is a new-build house on urban land with no mains sewer (fourth transitional provision of the Balearic Urban Planning Act, Law 12/2017), a prior notice goes first to the Balearic water authority, Recursos Hídrics, which is what the town hall asks for before granting the licence, and from then there are two years at most to file the responsible declaration (art. 70.5).
- Prior authorisation, a declaration is not enough, when the treated water goes to a soakaway trench or soakaway pit, however many bed spaces there are, or when the house has 12 population equivalents or more and lies within a well protection zone or 500 m or less from a wetland. For that authorisation, silence means refusal: if the DGRH does not answer, the answer is no.
- Above 12 population equivalents, the performance checks and the log of cleaning, maintenance and sludge must be sent to the DGRH every year (art. 70.11), and the pre-treatment includes grease removal. Below that, there is no annual filing.
Who does what. As the installation company we prepare and sign every document your architect asks for: the declaration that the installation meets the rules, the manufacturer's data sheets and performance, the maintenance plan and the certificate for the electrical installation. We hand them over ready to go, and your architect or technical adviser files them.
One tip that saves time: when someone says “the town hall wants it”, it is almost always the DGRH asking, as part of the responsible declaration.
Where the treated water goes, and where it cannot soak away
The general rule is to reuse it on your own plot, and that needs at least 25 m² of green area per population equivalent (art. 70.12): a house with 6 bed spaces needs 150 m² of garden. It is water that irrigates without drawing on a well or the mains. A soakaway trench is kept for justified cases, with a favourable report from the water authority.
The rest depends on where the plot is. If it lies in a zone of high aquifer vulnerability, the rules only allow a green area, not a trench, and also list denitrification and disinfection: recommended up to 12 population equivalents and required above 12; within the maximum-restriction zone of a public supply well, both are needed whatever the size (art. 70.10, tables 13 and 14). That is why we check the DGRH map viewer before giving you a price: it changes the unit.
And two things never go into the plant: rainwater (art. 70.7.d) and, in rural hotels and restaurants, fats without their grease separator upstream (art. 70.7.e).
Maintenance: three separate things
- Sludge emptying is done by an authorised waste-management company, as the law requires, as often as your unit's manufacturer specifies, and you keep the receipts for the last five years in case the authority asks (art. 70.7.f). You can check that the company is authorised in the Balearic government's public register of waste managers (RPGRIB).
- Our service visits: what the regulations require or, if the manufacturer asks for more, what it asks (on the GRAF one2clean, two a year), with a signed report. Blower and air filter, aeration, settling test, state of the biology, control panel and alarm, and the outlet water. At each visit we ask for the invoice of the last emptying and note it down.
- What you check between visits: every day, that the running light is green and no alarm is sounding; every month, that the outlet water is not cloudy and the inlet and outlet are not blocked. And don't switch off the plant's power when you close the house: without air, the bacteria die.
Bacteria from a bottle? Not as a routine, because continuous aeration keeps the biology alive. Only at start-up, after a full emptying or if it has suffered (antibiotics, lots of bleach, a house closed for months with the blower off).
How we work
How we work, step by step
You send us the details
The list above. With it we tell you whether we can quote straight away or need to see the site.
Written quote
The quote covers the unit, the installation, the electrics and the documents. The digging is done by your builder, and we give you in writing how the pit must be left according to the manufacturer.
Acceptance and date
You accept the quote and we agree the installation date with you.
Installation and documents
We install once the pit meets what we gave you in writing, commission the plant and hand over the signed documents for your architect to file.
If what you need is a new drainage network for the house (downpipes, rainwater, chambers), see drainage in Mallorca →. And if you live abroad and we installed your plant, its service visits can go into Villa Care →
Sewage treatment plants by area (west and centre): Palma · Andratx · Calvià · Llucmajor · Marratxí · Santa Maria del Camí · Binissalem
Treatment plants by area (east and south): Manacor · Porto Cristo · Felanitx · Cala d'Or · Santanyí · Campos
Treatment plants by area (north and Inca): Inca · Lloseta · Campanet · sa Pobla · Muro · Alcúdia · Pollença · Santa Margalida
Sewage treatment plants in more towns: Cala Ratjada · Cala Murada · Portocolom · Algaida · Sineu · Petra · Porreres · Llubí · Montuïri · Vilafranca de Bonany · Sant Joan · Santa Eugènia · Maria de la Salut · Costitx · Alaró · Consell · Sencelles · Selva · Sóller · Bunyola · Esporles
Quality
We work with all the main brands
We work with all brands; as an example, GRAF tanks. We propose the equipment case by case.
Common questions
Frequently asked questions about treatment plants
What do I need to send you for a quote?
The location of the house, its maximum number of bed spaces, whether it is a main or holiday home, where the treated water will go (garden, soakaway trench or pit), what is nearby (wells and wetlands, with their distance), photos of the drain outlet and of the tank spot, and your email. If there is a project, the drawings in DXF or DWG. With that we can almost always quote without a visit, and we reply within 24-48 hours on working days.
When is a prior authorisation needed, and when is a responsible declaration enough?
In Mallorca, a responsible declaration to the Direcció General de Recursos Hídrics is enough when the treated water is reused on your own plot. A prior authorisation is needed if it goes to a soakaway trench or pit, however many bed spaces there are, and also if the house has 12 population equivalents or more and lies within a well protection zone or 500 m or less from a wetland. For the authorisation, silence means refusal.
Which document must always be filed with Recursos Hídrics?
The responsible declaration of the installation, once the unit is installed and also below 12 population equivalents (art. 70.4 of the Balearic Water Plan, Royal Decree 49/2023). It carries four documents: proof of purchase and installation, technical specifications, performance and a maintenance plan. If it is a new-build house on urban land with no mains sewer, a prior notice goes first to the Balearic water authority, Recursos Hídrics (fourth transitional provision of the Balearic Urban Planning Act, Law 12/2017), and then there are two years at most to file it.
What changes if the house has more than 12 population equivalents?
Three things: the performance checks and the log of cleaning, maintenance and sludge must be sent to the DGRH every year (art. 70.11 of the Balearic Water Plan, Royal Decree 49/2023); the pre-treatment includes grease removal; and with 12 or more near public supply wells or a wetland, a prior authorisation is needed. For homes, the Plan's guideline equivalence is 1 population equivalent per bed space (art. 70.8), so two houses of 8 bed spaces with a unit each are not the same as one plant for 16.
What is the difference between a septic tank and an extended-aeration treatment plant?
A septic tank only settles: the solids stay and the water leaves almost as dirty. An extended-aeration plant blows air in with a blower and bacteria break down the organic load. The Balearic Water Plan requires a minimum performance of BOD₅ 70%, COD 75% and suspended solids 70% (art. 70.10), proven by the manufacturer under EN 12566-3. That is why we install treatment plants.
How much garden do I need for the treated water?
The Balearic Water Plan asks for at least 25 m² of green area per population equivalent (art. 70.12): 125 m² for 5 bed spaces and 250 m² for 10. It is water that irrigates the plot without drawing on a well or the mains. Without that much ground, the options are a soakaway trench with a favourable report from the water authority, or a sealed holding tank.
Where can the water not soak away through a trench?
If the plot lies in a zone of high aquifer vulnerability, the Balearic Water Plan (Royal Decree 49/2023) only allows discharge to a green area (art. 70.10, tables 13 and 14). The additional treatment it lists is denitrification and disinfection: for homes of up to 12 population equivalents, table 13 marks it as “recommended, not compulsory”; above 12, and within the maximum-restriction zone of a public supply well whatever the size, both are needed. We check the DGRH map viewer before giving you a price, because it changes the unit.
Who empties the plant, and how often?
An authorised company that you hire, as often as the manufacturer specifies (art. 70.7.f). On a GRAF one2clean it is decided by the SV30 settling test we run at the service visit: above 900 ml/l it is time to empty. Keep the receipts for the last five years, because in the Balearics the water authority can ask for them. The tankers may not discharge into the sewer, only into a public treatment works with authorisation (art. 71.4).
Who digs the pit?
Your builder: the digging, the sand bed and backfill, the trenches and the chambers. Our quote covers the unit, the installation, the electrics and the documents, and before anyone digs we give you in writing how the pit must be left according to the manufacturer, because if the tank settles badly the manufacturer's warranty (on a GRAF, for example) no longer covers it.
Who files the documents with Recursos Hídrics or the town hall?
As the installation company, we prepare and sign everything your architect asks for, including the declaration that the installation meets the rules, the manufacturer's data sheets and performance, the maintenance plan and the electrical certificate, and we hand it over ready to go. Your architect or technical adviser files it with the DGRH of the Balearic government (art. 70.4 of the Balearic Water Plan, Royal Decree 49/2023). And when someone says “the town hall wants it”, it is almost always the DGRH asking.
What happens if the house stands empty for months?
The blower has to keep running: if you switch off the power when you leave, the bacteria die and the plant does not treat when you come back. For a holiday home we add the carbon dosing module (Pack +C) to the GRAF one2clean, which feeds the bacteria while nobody is there. And the plant is sized for the most people who will stay, not for the yearly average.
Do I need to add bacteria?
Not as a routine: continuous aeration keeps the biology alive. Only at the start-up of a new installation, after a full emptying or if the biology has suffered (antibiotics, lots of bleach, a house closed for months with the blower off).
A house with no mains sewer, or an old cesspit to replace?
Send us the location, how many bed spaces the house has, where the water will go and a few photos. We reply within 24-48 hours on working days.