Water hardness and tap water in Stuttgart

Name: Water hardness and tap water in Stuttgart
Creator: Trinkwassermonitor
License: https://creativecommons.org/licenses/by/4.0/

Stuttgart, Baden-Württemberg · Postcode 70173, 70178, 70190, 70376, 70435, 70567 …

This page is a translation of the German version; the German page is authoritative. German version · Report a translation error

Short answer: The tap water in Stuttgart has a total hardness of 13.4 °dH, hardness range “medium” (as of 2025). All tested parameters with a legal limit (14) meet the limits set by the German Drinking Water Ordinance (TrinkwV). Source: test report by Landeswasserversorgung. WaterScore: 100 out of 100 (data coverage: 7 of 7 core parameters).

Limits of the Drinking Water OrdinancemetAll tested parameters (14), at the waterworks
Water hardness13.4 °dH, mediumNo legal limit, only a range
Data coverageCore parameters: 7 of 7Score based on complete data

Verified drinking-water values

Parameter	Value	Limit (TrinkwV)	Sampling date	Source	Status
Nitrate	21.2 mg/L 42 % of the limit	50 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Nitrite	< 0.01 mg/L	0.5 mg/L	2025	Zweckverband Landeswasserversorgung	verified
PFAS (sum)	0.002 µg/L	0.1 µg/L in force since 12 January 2026 from 12 January 2028: additionally PFAS-4 0.02 µg/L	2025	Zweckverband Landeswasserversorgung	verified
Lead	< 0.0005 mg/L	0.01 mg/L from 12 January 2028: 0.005 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Arsenic	< 0.0005 mg/L	0.01 mg/L new plants from 2028, all from 2036: 0.004 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Uranium	0.001 mg/L 10 % of the limit	0.01 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Mercury	< 0.00005 mg/L	0.001 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Copper	< 0.001 mg/L	2 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Cadmium	< 0.0001 mg/L	0.003 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Chromium	< 0.0005 mg/L	0.025 mg/L from 12 January 2030: 0.005 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Chloride	33.9 mg/L 14 % of the limit	250 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Sulphate	19.9 mg/L	250 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Sodium	13.1 mg/L	200 mg/L	2025	Zweckverband Landeswasserversorgung	verified
Calcium	77 mg/L	–	2025	Zweckverband Landeswasserversorgung	verified
Magnesium	11.3 mg/L	–	2025	Zweckverband Landeswasserversorgung	verified
pH	7.56	6.5–9.5	2025	Zweckverband Landeswasserversorgung	verified
Total hardness	13.4 °dH (medium)	no legal limit	2025	Zweckverband Landeswasserversorgung	verified
Electrical conductivity	528 µS/cm	–	2025	Zweckverband Landeswasserversorgung	verified

Note from the test report (in the German original): Landeswasserversorgung (LW) · Mittelwerte 2025 für Versorgungsbereich 1 (u. a. der nördliche, zentrale und östliche Teil Stuttgarts). Süden, Westen und Teile des Nordens werden von der Bodensee-Wasserversorgung mit etwas weicherem Wasser (~9 °dH) versorgt – beide liegen im Härtebereich „mittel“. In VB1/VB2 schwankt die Gesamthärte zwischen 11,5 und 14,0 °dH.

Is a value wrong or out of date? Report an error – we check every report against the original source.

Water at your own tap: The values describe the water the supplier delivers – not automatically the water at your tap. The water supplier is responsible up to the service connection (Hausanschluss); the building owner is responsible for the pipes beyond it. Lead can dissolve from lead pipes, leaded solder joints or old brass fittings, especially when water has stood in the pipes for a long time (stagnant water); this mainly affects buildings constructed before about 1973. If water has stood in the pipes for several hours, let it run until it comes out cool. If you suspect lead pipes, a lead analysis of the stagnant water by an accredited laboratory will help.

Background on household plumbing, not a measurement: in Stuttgart, 68 % of buildings with living space were built before 1970, and a further 8 % between 1970 and 1979 (Zensus 2022, Statistisches Bundesamt, dl-de/by-2-0). (Zensus 2022) According to the German Environment Agency (Umweltbundesamt), lead pipes exist at most in houses built before 1973 – and by no means in all of them. Whether there are any in your house is known to the owner or a plumber. (UBA)

What the values mean for Stuttgart

Nitrate 21.2 mg/L – about 42 % of the limit of 50 mg/L and comparatively high for a city waterworks; the cause is usually nitrate from agriculture entering the raw water. Boiling does not reduce nitrate.
PFAS (sum of PFAS-20) 2 ng/L – about 2 % of the limit of 100 ng/L (since 12 January 2026).
Lead – not detectable at the waterworks. Lead gets into the water almost only through old lead pipes in household plumbing, not via the supplier.
Uranium 1 µg/L – unremarkable against a limit of 10 µg/L. In some regions uranium occurs naturally from the rock (geogenic).
pH 7.56 – within the range of the Drinking Water Ordinance (6.5 to 9.5). The pH determines how corrosive the water is in household plumbing.

Water hardness in Stuttgart in everyday life

At 13.4 °dH, Stuttgart is in the hardness range “medium” (soft: below 8.4 °dH, medium: 8.4–14 °dH, hard: above 14 °dH).

Dose detergent for the hardness range “medium”.
As a rule of thumb, descale the kettle about every four to six weeks and the coffee machine as the manufacturer recommends.
A limescale protection device is not a must at medium hardness; regular descaling is often enough.

Baby food and low sodium: tap water in Stuttgart next to the bottled-water thresholds

Bottled water may only be labelled “suitable for preparing infant food” („geeignet für die Zubereitung von Säuglingsnahrung“) if it keeps to the maximum levels of the German Mineral and Table Water Ordinance (Mineral- und Tafelwasser-Verordnung, Annex 6). Here the published values for Stuttgart are shown next to them, each substance on its own. This is a comparison with labelling thresholds for bottled water, not a statement on whether your tap water is suitable for baby food. (Min/TafelWV, Anlage 6)

Values at the waterworks next to the maximum levels for bottled water “suitable for infant food”
Substance	Maximum level	Value in Stuttgart
Sodium	20 mg/l	13.1 mg/l – not above
Nitrate	10 mg/l	21.2 mg/l – above
Nitrite	0.02 mg/l	below the detection limit (0.01 mg/l) – not above
Sulphate	240 mg/l	19.9 mg/l – not above
Fluoride	0.7 mg/l	not in the report
Manganese	0.05 mg/l	not in the report
Arsenic	0.005 mg/l	below the detection limit (0.0005 mg/l) – not above
Uranium	0.002 mg/l	0.001 mg/l – not above

Against the other thresholds of Annex 6, the water would qualify as: low in sodium (“suitable for a low-sodium diet”) (Sodium 13.1 mg/l, threshold below 20 mg/l).

For context: the German Environment Agency (Umweltbundesamt) considers preparing baby food with bottled water carrying this label necessary only in rare cases, for example when tap water is temporarily allowed to contain more than 50 mg/l nitrate. (UBA 2016, p. 59) Water from lead pipes in the house is always unsuitable for infants. (UBA 2020, p. 16) The values apply at the waterworks. Questions about baby food are answered by your midwife, your paediatrician and the health office (Gesundheitsamt).

Frequently asked questions about tap water in Stuttgart

Can you drink the tap water in Stuttgart?

According to the verified values, yes: All tested parameters with a legal limit (14) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore: 100 out of 100 (data coverage: 7 of 7 core parameters). This applies to the water from the waterworks – restrictions can only arise from old household plumbing.

How hard is the water in Stuttgart?

The total hardness is 13.4 °dH – hardness range “medium”. Dose detergent for the hardness range “medium”.

Is there PFAS in the tap water in Stuttgart?

Yes, in measurable amounts: according to the published analysis by Landeswasserversorgung (as of 2025), the sum of PFAS-20 is 0.002 (middle of the range given by the supplier) µg/l – that is 2 % of the limit of 0.1 µg/l, which has applied since 12 January 2026.

Do I need to filter my tap water in Stuttgart?

Based on the verified supplier values, a filter is not necessary. It can make sense if you do not like the taste. If you suspect lead pipes in an old building, a filter does not help; a laboratory analysis at the tap does – that is a question of the household plumbing, not of the water leaving the works.

Is the nitrate level in Stuttgart a concern?

The value of 21.2 mg/L is below the limit of 50 mg/L, but higher than in many other evaluated cities. The limit of the Drinking Water Ordinance also applies to preparing baby food; mineral water labelled “suitable for preparing infant food” („geeignet für die Zubereitung von Säuglingsnahrung“) may contain at most 10 mg/L nitrate. Boiling does not help against nitrate.

WaterScore

Total100 / 100
Chemical safety100 / 100
Heavy metals100 / 100
PFAS100 / 100
Nutrients100 / 100
General parameters100 / 100
Data timeliness100 / 100
Data quality100 / 100

Data coverage: 7 of 7 core parameters. Missing parameters are neither estimated nor counted as harmless: the score is based only on the values available. It is not a health assessment and says nothing about the water beyond the service connection. Methodology v3: how we calculate the WaterScore.

Evidence: cite and check

Trinkwasseranalyse 2025 – Versorgungsbereich 1, Mittelwerte 2025 (Zweckverband Landeswasserversorgung) · SHA-256 of the evaluated file: d0dfecad396085ff…, checked on 3 October 2026

Suggested citation: Trinkwassermonitor (2025): Tap water in Stuttgart. Values according to the water supplier’s test report, sampling date 2025; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/stuttgart/

JSON: /api/v1/evidence?city=stuttgart

Data as of: 2025 · verified: 18 of 18 evaluated parameters.

This page shows only verified test data with sources, or states explicitly where data is missing (no estimated values). Cite as: “Trinkwassermonitor (2026). Tap water in Stuttgart. Retrieved from https://trinkwassermonitor.ink/en/tap-water/stuttgart/.”