Sewage treatment plants in Mallorca
Septic tank, treatment plant or holding tank, the documents and maintenance, in detail.
See the guide →Treatment plants · Sant Joan
Sewage treatment plants in Sant Joan, for fincas and agroturismos
Almost the whole municipality of Sant Joan is countryside, and its fincas and agroturismos treat their own water. The Water Plan keeps a close eye on this area: the aquifer has high nitrate levels and the Hortella stream, which drains this land, is in poor status. 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 engineer.
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
- Agroturismos and fincas
- Since 1998
GRAF one2clean · Image: GRAF
Your village
What the Water Plan says about the water in Sant Joan
Two entries in Annex 9 of the Water Plan concern Sant Joan: that of the Petra groundwater body (1815M4), over which the village lies, and that of the Hortella stream, the headwaters of the Na Borges stream.
Nitrates in the aquifer
The Petra body covers 155 km² of the Pla and is shared by nine municipalities. It is in poor chemical status because of nitrates: 98 mg/l on average. The Plan notes that it has improved a great deal —the historical average was 214 mg/l— but not enough, and expects to designate it a zone vulnerable to nitrates from agriculture.
The Hortella stream
It is the upper part of the Na Borges stream, with a 25 km² catchment, almost all on rural land. The Plan lists it in poor status, with phosphates and nitrates, something the Plan itself considers characteristic of waters affected by discharges, and its general measures include reducing the pollution load on rural land. The treated water from a finca does not go into the stream: it goes to its green area.
A heavily abstracted aquifer
The Petra body has an abstraction index of 99 %, and the Plan asks for abstraction to be cut by 20 %. Irrigating the garden with the house's treated water, as art. 70.12 requires, is water that does not come out of the well.
The rules here
Agroturismos and rural houses: how bed spaces are counted
Table 12 of the Water Plan gives the guideline equivalences: in homes, rural houses and agroturismos, one population equivalent per bed space; a worker who lives on the finca counts as one, and one who does not live there, a quarter; in restaurants and event venues, a quarter per seat. The Plan asks for the capacity to be justified by use and occupancy (art. 70.8); we size it for the maximum, not the average.
In hospitality, agroturismos included, a grease separator before the treatment plant is compulsory (art. 70.7.e). And above 12 population equivalents, the performance checks and the maintenance and sludge log must be sent to the DGRH every year (art. 70.11).
What we do
What we do in Sant Joan, and what others do
- Bed spaces counted for the busiest day: guests, staff living on the finca and event guests (table 12 of the Plan). With that we choose the new treatment plant, approved with CE marking and EN 12566 (art. 70.14); we work with all brands, for example the GRAF one2clean.
- Installation, electrics and commissioning, as a licensed low-voltage installation company, with the grease separator that hospitality requires ahead of the treatment plant (art. 70.7.e). We don't subcontract anyone.
- The documents for the responsible declaration (art. 70.4), prepared and signed as the installation company and submitted by your engineer; if the agroturismo goes above 12 population equivalents, we explain the annual submission of the performance check and sludge log (art. 70.11).
- The excavation is done by your builder, following what we give them in writing according to the manufacturer, and the sludge is emptied by an authorised waste company (art. 70.7.f). The treated water goes to your green area, not to the torrent.
- 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 when the finca closes and the blower keeps running.
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 “Petra (1815M4)” and the surface water body “Hortella (11016801)” · EN 12566 · manufacturer's manual (GRAF one2clean, as an example).
How we work
How we do it in Sant Joan, in 3 steps
1
Capacity, staff and the torrent
Tell us the bed spaces, who lives on the finca, whether there are weddings or meals and whether the torrent runs nearby. With the location we check the vulnerability of the Petra aquifer on the DGRH map.
2
A quote for the full day
We size the plant for the day with the most people, not the average, and send you in writing the unit, grease separator, installation, electrics and documents.
3
Installation and documents
Once the pit is ready, we install and commission. We hand over the signed documents for your engineer and explain what to do with the unit when the agroturismo closes.
Common questions
Frequently asked questions about treatment plants in Sant Joan
I run an agroturismo with 14 bed spaces in Sant Joan: which treatment plant do I need?
One sized for at least 14 population equivalents, plus one for each worker who lives on the finca and a quarter for each one who does not (table 12 of the Balearic Water Plan, Royal Decree 49/2023). Above 12, the pre-treatment includes grease removal (table 14), the grease separator is compulsory in hospitality (art. 70.7.e) and the performance checks are sent to the DGRH every year (art. 70.11).
Can I discharge the treated water into the stream that runs through the finca?
As a rule, no. The Water Plan requires it to be reused on the plot, with 25 m² of green area per population equivalent (art. 70.12 of the Balearic Water Plan, Royal Decree 49/2023); any other destination needs a discharge authorisation (art. 70.1). The Hortella stream, in whose catchment Sant Joan lies, is also listed in poor status because of phosphates and nitrates in Annex 9 of the Plan.
Why is there so much concern about nitrates in the Pla?
Because the groundwater has very high levels of them. The Petra body, under Sant Joan, has an average of 98 mg/l of nitrates according to Annex 9 of the Balearic Water Plan, and the Plan expects to designate it a vulnerable zone. If your plot falls in a high-vulnerability zone of the aquifer, the rules only allow a green area and list denitrification and disinfection, recommended up to 12 population equivalents and compulsory above (art. 70.10, tables 13 and 14): we check it on the DGRH map.
My finca hosts weddings and meals: does the treatment plant change?
Yes, because the guests add load. Table 12 of the Balearic Water Plan (Royal Decree 49/2023) counts a quarter of a population equivalent per seat in restaurants and event venues. In addition, in hospitality the pre-treatment for oils and grease is compulsory (art. 70.7.e). Tell us how many people come on your busiest day: the treatment plant is sized for that day.
My agroturismo closes in winter: do I switch the treatment plant off?
No. The bacteria that treat the water need air 24 hours a day; if the blower is switched off, the biology suffers and, when you reopen, the plant takes time to treat the water again. For seasonal houses and accommodation there are units that feed carbon while nobody is there (on the GRAF one2clean, for example, the Pack +C). If treatment is not feasible because of seasonal use, the Balearic Water Plan accepts a sealed holding tank (art. 70.2.b).
Keep learning
More for your home in Sant Joan
The general guide to treatment plants and what else we do in Sant Joan.
Solar panels in Sant Joan
What a roof in Sant Joan produces according to PVGIS, the permits and the grants.
Solar panels in Sant Joan →Heat pumps in Sant Joan
Heating, hot water and cooling from one heat pump, and the FACTOR 2026 grant.
Heat pumps in Sant Joan →In the Pla and across Mallorca
Sewage treatment plants in the Pla de Mallorca: Montuïri · Vilafranca de Bonany · Santa Eugènia · Maria de la Salut · Costitx. Also nearby: Manacor · Inca · Palma, or see the guide to sewage treatment plants in Mallorca →
Need the house drainage (downpipes, rainwater, chambers)? Drainage in Mallorca →
Also in Sant Joan: air conditioning
See our work and customer reviews on the JSL Google Maps profile →
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 agroturismo in Sant Joan with no mains sewer?
Send us the location, the bed spaces, whether there are workers or events and a few photos. We reply within 24-48 hours on working days.