Italy · Comune

Drinking water in Nemi

3 supply zones, published by ACEA ATO 2 S.p.A.. The values come from the publications of the Italian water suppliers (gestori), which D.Lgs. 18/2023 requires of them from 12 January 2026. Italian parametric values apply: trihalomethanes 30 instead of 50 µg/l, chromium 25 µg/l, uranium 30 instead of 10 µg/l; for hardness there is no maximum value, it is given in French degrees (°F).

ZONA 1 CALVARIONE

ACEA ATO 2 S.p.A.

Water hardness

21.1 °dH

Key values ZONA 1 CALVARIONE
Parameter	Value	Parametric value	Share of the parametric value	Reference
Sum of PFAS	<0,10 µg/L below limit of quantification	0.1 µg/l	< 100 % *	Median
Nitrate	13,90 mg/L NO3	50 mg/l	28 %	Median
Lead	<0,2 µg/L Pb below limit of quantification	10 µg/l	—	Median
Escherichia coli (E. coli)	Conforme MPN/100 mL	0/100 ml	—	Median
Sulphate	3,29 mg/L SO4	250 mg/l	1 %	Median
Sodium	38,2 mg/L Na	200 mg/l	19 %	Median

* Value below the limit of quantification: the actual share of the parametric value is not known; it lies somewhere below the stated upper bound. The marker shows where the limit of quantification of the measurement lies relative to the parametric value.

Show all recorded parameters (61 — most recent value per parameter)

Microbiology (2)

Microbiology – ZONA 1 CALVARIONE
Parameter	Value	Parametric value	Share of the parametric value	Reference
Escherichia coli (E. coli)	Conforme MPN/100 mL	0/100 ml	—	Median
Intestinal enterococci	Conforme N/100 mL	0/100 ml	—	Median

Chemical parameters (28)

Chemical parameters – ZONA 1 CALVARIONE
Parameter	Value	Parametric value	Share of the parametric value	Reference
1,2-dichloroethane	<0,1 µg/L below limit of quantification	3 µg/l	< 3 % *	Median
Acrylamide	<0,03 µg/L below limit of quantification	0.1 µg/l	< 30 % *	Median
Antimony	<1,0 µg/L Sb below limit of quantification	10 µg/l	—	Median
Arsenic	3,90 µg/L As	10 µg/l	39 %	Median
Bisphenol A	<0,25 µg/L below limit of quantification	2.5 µg/l	< 10 % *	Median
Boron	0,078 mg/L B	1.5 mg/l	—	Median
Cadmium	<0,2 µg/L Cd below limit of quantification	5 µg/l	—	Median
Chlorate	<0,05 mg/L ClO3 below limit of quantification	0,25 — bzw. 0,70 bei Desinfektion mit Chlordioxid	—	Median
Chlorite	<0,05 mg/L ClO2 below limit of quantification	0,25 — bzw. 0,70 bei Desinfektion mit Chlordioxid	—	Median
Chromium	<5,0 µg/L Cr below limit of quantification	25 µg/l	—	Median
Copper	0,002 mg/L Cu	2 mg/l	—	Median
Cyanide	<10 µg/L CN below limit of quantification	50 µg/l	—	Median
Epichlorohydrin	<0,05 µg/L below limit of quantification	0.1 µg/l	< 50 % *	Median
Fluoride	0,23 mg/L	1.5 mg/l	15 %	Median
Haloacetic acids (HAA)	- µg/L not determined	60 µg/l	—	Median
Lead	<0,2 µg/L Pb below limit of quantification	10 µg/l	—	Median
Mercury	<0,2 µg/L Hg below limit of quantification	1 µg/l	—	Median
Nickel	<2,0 µg/L Ni below limit of quantification	20 µg/l	—	Median
Nitrate	13,90 mg/L NO3	50 mg/l	28 %	Median
Nitrite	<0,05 mg/L NO2 below limit of quantification	0.5 mg/l	< 10 % *	Median
Pesticides — Total	- µg/L not determined	0.5 µg/l	—	Median
Polycyclic aromatic hydrocarbons	- µg/L not determined	0.1 µg/l	—	Median
Selenium	<1,0 µg/L Se below limit of quantification	20 µg/l	—	Median
Tetrachloroethene	<1,0 µg/L below limit of quantification	—	—	Median
Trichloroethene	<1,0 µg/L below limit of quantification	—	—	Median
Trihalomethanes — Total	<1,0 µg/L below limit of quantification	30 µg/l	< 3 % *	Median
Uranium	12,52 µg/L U	30 µg/l	—	Median
Vinyl chloride	<0,1 µg/L below limit of quantification	0.5 µg/l	< 20 % *	Median

PFAS (1)

PFAS – ZONA 1 CALVARIONE
Parameter	Value	Parametric value	Share of the parametric value	Reference
Sum of PFAS	<0,10 µg/L below limit of quantification	0.1 µg/l	< 100 % *	Median

Indicator parameters (16)

Indicator parameters – ZONA 1 CALVARIONE
Parameter	Value	Parametric value	Share of the parametric value	Reference
Aluminium	8,0 µg/L Al	0.2 mg/l	—	Median
Ammonium	<0,1 mg/L NH4 below limit of quantification	0.5 mg/l	< 20 % *	Median
Chloride	13,3 mg/L Cl	250 mg/l	5 %	Median
Coliform bacteria	Conforme MPN/100 mL	0/100 ml	—	Median
Colour	Incolore Scala Pt/C	accettabile per i consumatori, senza variazioni anomale	—	Median
Conductivity (25 °C)	893 µS/cm	2,500 µS/cm	—	Median
Iron	18,0 µg/L Fe	0.2 mg/l	—	Median
Manganese	0,40 µg/L Mn	50 µg/l	—	Median
Odour	0 Diluiz. 25	accettabile per i consumatori, senza variazioni anomale	—	Median
pH	6,70 pH	6,5–9,5	—	Median
Sodium	38,2 mg/L Na	200 mg/l	19 %	Median
Sulphate	3,29 mg/L SO4	250 mg/l	1 %	Median
Taste	0 tasso diluz.	accettabile per i consumatori, senza variazioni anomale	—	Median
Temperature	11,8 °C	—	—	Median
Total organic carbon (TOC)	0,53 mg/L C	senza variazioni anomale	—	Median
Turbidity	<0,5 NTU below limit of quantification	accettabile per i consumatori, senza variazioni anomale	—	Median

Treatment substances (1)

Treatment substances – ZONA 1 CALVARIONE
Parameter	Value	Parametric value	Share of the parametric value	Reference
Free chlorine	0,11 mg/L Cl2	—	—	Median

Further parameters (13)

Further parameters – ZONA 1 CALVARIONE
Parameter	Value	Parametric value	Share of the parametric value	Reference
Acid capacity to pH 4.3	519 mg/L CaCO3	—	—	Median
Beryllium	0,40 µg/L Be	—	—	Median
Bromide	<50 µg/L Br below limit of quantification	—	—	Median
Calcium	96,10 mg/L Ca	—	—	Median
Dry residue	677 mg/L	—	—	Median
Hydrogen carbonate	633 mg/L HCO3	—	—	Median
Magnesium	33,00 mg/L Mg	—	—	Median
Phosphate	266 µg/L P2O5	—	—	Median
Potassium	69,10 mg/L K	—	—	Median
Silicate / silicic acid	57,7 mg/L SiO2	—	—	Median
Thallium	<0,2 µg/L Tl below limit of quantification	—	—	Median
Total hardness	37,6 °F	—	—	Median
Vanadium	24,40 µg/L V	0.14 mg/l	—	Median

Values taken unchanged from the publications linked below — for each parameter the most recent recorded value. „—" in the parametric value column: no currently valid legal parametric value is stored in our database for this parameter; the parameter register with all parametric values is being expanded continuously.

Source: https://www.aceaato2.a-acqua.it/content/dam/acea-ato2/pdf/it/mappe-qualita/nemi_zona_1_calvarione.pdf · luglio 2026 · luglio 2026 · retrieved on 08/07/2026

Zona 2 Villa delle Querce

ACEA ATO 2 S.p.A.

Water hardness

17.8 °dH

Key values Zona 2 Villa delle Querce
Parameter	Value	Parametric value	Share of the parametric value	Reference
Sum of PFAS	<0,10 µg/L below limit of quantification	0.1 µg/l	< 100 % *	Median
Nitrate	13,60 mg/L NO3	50 mg/l	27 %	Median
Lead	0,40 µg/L Pb	10 µg/l	—	Median
Escherichia coli (E. coli)	Conforme MPN/100 mL	0/100 ml	—	Median
Sulphate	5,03 mg/L SO4	250 mg/l	2 %	Median
Sodium	35,4 mg/L Na	200 mg/l	18 %	Median

Show all recorded parameters (61 — most recent value per parameter)

Microbiology (2)

Microbiology – Zona 2 Villa delle Querce
Parameter	Value	Parametric value	Share of the parametric value	Reference
Escherichia coli (E. coli)	Conforme MPN/100 mL	0/100 ml	—	Median
Intestinal enterococci	Conforme N/100 mL	0/100 ml	—	Median

Chemical parameters (28)

Chemical parameters – Zona 2 Villa delle Querce
Parameter	Value	Parametric value	Share of the parametric value	Reference
1,2-dichloroethane	<0,1 µg/L below limit of quantification	3 µg/l	< 3 % *	Median
Acrylamide	<0,03 µg/L below limit of quantification	0.1 µg/l	< 30 % *	Median
Antimony	<1,0 µg/L Sb below limit of quantification	10 µg/l	—	Median
Arsenic	4,70 µg/L As	10 µg/l	47 %	Median
Bisphenol A	<0,25 µg/L below limit of quantification	2.5 µg/l	< 10 % *	Median
Boron	0,056 mg/L B	1.5 mg/l	—	Median
Cadmium	<0,2 µg/L Cd below limit of quantification	5 µg/l	—	Median
Chlorate	<0,05 mg/L ClO3 below limit of quantification	0,25 — bzw. 0,70 bei Desinfektion mit Chlordioxid	—	Median
Chlorite	<0,05 mg/L ClO2 below limit of quantification	0,25 — bzw. 0,70 bei Desinfektion mit Chlordioxid	—	Median
Chromium	<5,0 µg/L Cr below limit of quantification	25 µg/l	—	Median
Copper	<0,001 mg/L Cu below limit of quantification	2 mg/l	—	Median
Cyanide	<10 µg/L CN below limit of quantification	50 µg/l	—	Median
Epichlorohydrin	<0,05 µg/L below limit of quantification	0.1 µg/l	< 50 % *	Median
Fluoride	0,26 mg/L	1.5 mg/l	17 %	Median
Haloacetic acids (HAA)	- µg/L not determined	60 µg/l	—	Median
Lead	0,40 µg/L Pb	10 µg/l	—	Median
Mercury	<0,2 µg/L Hg below limit of quantification	1 µg/l	—	Median
Nickel	<2,0 µg/L Ni below limit of quantification	20 µg/l	—	Median
Nitrate	13,60 mg/L NO3	50 mg/l	27 %	Median
Nitrite	<0,05 mg/L NO2 below limit of quantification	0.5 mg/l	< 10 % *	Median
Pesticides — Total	- µg/L not determined	0.5 µg/l	—	Median
Polycyclic aromatic hydrocarbons	- µg/L not determined	0.1 µg/l	—	Median
Selenium	<1,0 µg/L Se below limit of quantification	20 µg/l	—	Median
Tetrachloroethene	<1,0 µg/L below limit of quantification	—	—	Median
Trichloroethene	<1,0 µg/L below limit of quantification	—	—	Median
Trihalomethanes — Total	<1,0 µg/L below limit of quantification	30 µg/l	< 3 % *	Median
Uranium	9,50 µg/L U	30 µg/l	—	Median
Vinyl chloride	<0,1 µg/L below limit of quantification	0.5 µg/l	< 20 % *	Median

PFAS (1)

PFAS – Zona 2 Villa delle Querce
Parameter	Value	Parametric value	Share of the parametric value	Reference
Sum of PFAS	<0,10 µg/L below limit of quantification	0.1 µg/l	< 100 % *	Median

Indicator parameters (16)

Indicator parameters – Zona 2 Villa delle Querce
Parameter	Value	Parametric value	Share of the parametric value	Reference
Aluminium	3,1 µg/L Al	0.2 mg/l	—	Median
Ammonium	<0,1 mg/L NH4 below limit of quantification	0.5 mg/l	< 20 % *	Median
Chloride	15,2 mg/L Cl	250 mg/l	6 %	Median
Coliform bacteria	Conforme MPN/100 mL	0/100 ml	—	Median
Colour	Incolore Scala Pt/C	accettabile per i consumatori, senza variazioni anomale	—	Median
Conductivity (25 °C)	814 µS/cm	2,500 µS/cm	—	Median
Iron	7,9 µg/L Fe	0.2 mg/l	—	Median
Manganese	0,50 µg/L Mn	50 µg/l	—	Median
Odour	0 Diluiz. 25	accettabile per i consumatori, senza variazioni anomale	—	Median
pH	7,20 pH	6,5–9,5	—	Median
Sodium	35,4 mg/L Na	200 mg/l	18 %	Median
Sulphate	5,03 mg/L SO4	250 mg/l	2 %	Median
Taste	0 tasso diluz.	accettabile per i consumatori, senza variazioni anomale	—	Median
Temperature	16,0 °C	—	—	Median
Total organic carbon (TOC)	0,56 mg/L C	senza variazioni anomale	—	Median
Turbidity	<0,5 NTU below limit of quantification	accettabile per i consumatori, senza variazioni anomale	—	Median

Treatment substances (1)

Treatment substances – Zona 2 Villa delle Querce
Parameter	Value	Parametric value	Share of the parametric value	Reference
Free chlorine	0,22 mg/L Cl2	—	—	Median

Further parameters (13)

Further parameters – Zona 2 Villa delle Querce
Parameter	Value	Parametric value	Share of the parametric value	Reference
Acid capacity to pH 4.3	443 mg/L CaCO3	—	—	Median
Beryllium	<0,2 µg/L Be below limit of quantification	—	—	Median
Bromide	<50 µg/L Br below limit of quantification	—	—	Median
Calcium	82,40 mg/L Ca	—	—	Median
Dry residue	582 mg/L	—	—	Median
Hydrogen carbonate	540 mg/L HCO3	—	—	Median
Magnesium	27,10 mg/L Mg	—	—	Median
Phosphate	180 µg/L P2O5	—	—	Median
Potassium	60,60 mg/L K	—	—	Median
Silicate / silicic acid	41,4 mg/L SiO2	—	—	Median
Thallium	<0,2 µg/L Tl below limit of quantification	—	—	Median
Total hardness	31,7 °F	—	—	Median
Vanadium	35,60 µg/L V	0.14 mg/l	—	Median

Source: https://www.aceaato2.a-acqua.it/content/dam/acea-ato2/pdf/it/mappe-qualita/nemi_zona_2_villa_delle_querce.pdf · luglio 2026 · luglio 2026 · retrieved on 08/07/2026

ZONA 3 LAGO

ACEA ATO 2 S.p.A.

Water hardness

16.3 °dH

Key values ZONA 3 LAGO
Parameter	Value	Parametric value	Share of the parametric value	Reference
Sum of PFAS	<0,10 µg/L below limit of quantification	0.1 µg/l	< 100 % *	Median
Nitrate	16,70 mg/L NO3	50 mg/l	33 %	Median
Lead	<0,2 µg/L Pb below limit of quantification	10 µg/l	—	Median
Escherichia coli (E. coli)	Conforme MPN/100 mL	0/100 ml	—	Median
Sulphate	55,35 mg/L SO4	250 mg/l	22 %	Median
Sodium	27,7 mg/L Na	200 mg/l	14 %	Median

Show all recorded parameters (61 — most recent value per parameter)

Microbiology (2)

Microbiology – ZONA 3 LAGO
Parameter	Value	Parametric value	Share of the parametric value	Reference
Escherichia coli (E. coli)	Conforme MPN/100 mL	0/100 ml	—	Median
Intestinal enterococci	Conforme N/100 mL	0/100 ml	—	Median

Chemical parameters (28)

Chemical parameters – ZONA 3 LAGO
Parameter	Value	Parametric value	Share of the parametric value	Reference
1,2-dichloroethane	<0,1 µg/L below limit of quantification	3 µg/l	< 3 % *	Median
Acrylamide	µg/L not determined	0.1 µg/l	—	Median
Antimony	<1,0 µg/L Sb below limit of quantification	10 µg/l	—	Median
Arsenic	4,95 µg/L As	10 µg/l	50 %	Median
Bisphenol A	<0,25 µg/L below limit of quantification	2.5 µg/l	< 10 % *	Median
Boron	0,080 mg/L B	1.5 mg/l	—	Median
Cadmium	<0,2 µg/L Cd below limit of quantification	5 µg/l	—	Median
Chlorate	<0,05 mg/L ClO3 below limit of quantification	0,25 — bzw. 0,70 bei Desinfektion mit Chlordioxid	—	Median
Chlorite	<0,05 mg/L ClO2 below limit of quantification	0,25 — bzw. 0,70 bei Desinfektion mit Chlordioxid	—	Median
Chromium	<5,0 µg/L Cr below limit of quantification	25 µg/l	—	Median
Copper	0,001 mg/L Cu	2 mg/l	—	Median
Cyanide	<10 µg/L CN below limit of quantification	50 µg/l	—	Median
Epichlorohydrin	µg/L not determined	0.1 µg/l	—	Median
Fluoride	0,40 mg/L	1.5 mg/l	27 %	Median
Haloacetic acids (HAA)	µg/L not determined	60 µg/l	—	Median
Lead	<0,2 µg/L Pb below limit of quantification	10 µg/l	—	Median
Mercury	<0,2 µg/L Hg below limit of quantification	1 µg/l	—	Median
Nickel	<2,0 µg/L Ni below limit of quantification	20 µg/l	—	Median
Nitrate	16,70 mg/L NO3	50 mg/l	33 %	Median
Nitrite	<0,05 mg/L NO2 below limit of quantification	0.5 mg/l	< 10 % *	Median
Pesticides — Total	- µg/L not determined	0.5 µg/l	—	Median
Polycyclic aromatic hydrocarbons	- µg/L not determined	0.1 µg/l	—	Median
Selenium	<1,0 µg/L Se below limit of quantification	20 µg/l	—	Median
Tetrachloroethene	<1,0 µg/L below limit of quantification	—	—	Median
Trichloroethene	<1,0 µg/L below limit of quantification	—	—	Median
Trihalomethanes — Total	<1,0 µg/L below limit of quantification	30 µg/l	< 3 % *	Median
Uranium	24,60 µg/L U	30 µg/l	—	Median
Vinyl chloride	µg/L not determined	0.5 µg/l	—	Median

PFAS (1)

PFAS – ZONA 3 LAGO
Parameter	Value	Parametric value	Share of the parametric value	Reference
Sum of PFAS	<0,10 µg/L below limit of quantification	0.1 µg/l	< 100 % *	Median

Indicator parameters (16)

Indicator parameters – ZONA 3 LAGO
Parameter	Value	Parametric value	Share of the parametric value	Reference
Aluminium	1,2 µg/L Al	0.2 mg/l	—	Median
Ammonium	<0,1 mg/L NH4 below limit of quantification	0.5 mg/l	< 20 % *	Median
Chloride	19,4 mg/L Cl	250 mg/l	8 %	Median
Coliform bacteria	Conforme MPN/100 mL	0/100 ml	—	Median
Colour	Incolore Scala Pt/C	accettabile per i consumatori, senza variazioni anomale	—	Median
Conductivity (25 °C)	697 µS/cm	2,500 µS/cm	—	Median
Iron	6,8 µg/L Fe	0.2 mg/l	—	Median
Manganese	0,35 µg/L Mn	50 µg/l	—	Median
Odour	0 Diluiz. 25	accettabile per i consumatori, senza variazioni anomale	—	Median
pH	7,15 pH	6,5–9,5	—	Median
Sodium	27,7 mg/L Na	200 mg/l	14 %	Median
Sulphate	55,35 mg/L SO4	250 mg/l	22 %	Median
Taste	0 tasso diluz.	accettabile per i consumatori, senza variazioni anomale	—	Median
Temperature	13,8 °C	—	—	Median
Total organic carbon (TOC)	1,10 mg/L C	senza variazioni anomale	—	Median
Turbidity	<0,5 NTU below limit of quantification	accettabile per i consumatori, senza variazioni anomale	—	Median

Treatment substances (1)

Treatment substances – ZONA 3 LAGO
Parameter	Value	Parametric value	Share of the parametric value	Reference
Free chlorine	0,18 mg/L Cl2	—	—	Median

Further parameters (13)

Further parameters – ZONA 3 LAGO
Parameter	Value	Parametric value	Share of the parametric value	Reference
Acid capacity to pH 4.3	316 mg/L CaCO3	—	—	Median
Beryllium	<0,2 µg/L Be below limit of quantification	—	—	Median
Bromide	50 µg/L Br	—	—	Median
Calcium	84,30 mg/L Ca	—	—	Median
Dry residue	498 mg/L	—	—	Median
Hydrogen carbonate	385 mg/L HCO3	—	—	Median
Magnesium	19,60 mg/L Mg	—	—	Median
Phosphate	232 µg/L P2O5	—	—	Median
Potassium	40,30 mg/L K	—	—	Median
Silicate / silicic acid	40,1 mg/L SiO2	—	—	Median
Thallium	<0,2 µg/L Tl below limit of quantification	—	—	Median
Total hardness	29,1 °F	—	—	Median
Vanadium	21,80 µg/L V	0.14 mg/l	—	Median

Source: https://www.aceaato2.a-acqua.it/content/dam/acea-ato2/pdf/it/mappe-qualita/nemi_zona_3_lago.pdf · luglio 2026 · luglio 2026 · retrieved on 08/07/2026

How to read the share of the parametric value

12 % Share of the parametric value. The proportion of the permitted maximum that the measured value uses — here 12 %, so just over an eighth.

< 10 % * Below the limit of quantification. The substance was not detectable. The mark shows where the detection limit lies relative to the parametric value — the actual share of the parametric value is below that.

Several samples per year: for chemical parameters the mean value is given, for microbiological ones the highest measured value. There the parametric value is zero — a single finding would disappear in the average, and it is precisely that finding which is the information. Which reference applies is stated in the last column of the table.

Legal basis: Art. 18 D.Lgs. 18/2023 as amended by D.Lgs. 102/2025 (transposition of EU Directive 2020/2184). The values are not official — the publication of the Gestore, to which every row links, remains authoritative. Assignment of the comune: information in the analysis document, resolved against the municipality list of ISTAT (territorial status 01.01.2026, CC BY 4.0).