Water hardness and tap water in Weimar
Weimar, Thüringen · Postcode 99423, 99425, 99427, 99428
This page is a translation of the German version; the German page is authoritative. German version · Report a translation error
- Limits of the Drinking Water OrdinancemetAll tested parameters (16), at the waterworks
- Water hardness13 °dH, mediumNo legal limit, only a range
- Data coverageCore parameters: 6 of 7Score based on complete data
Verified drinking-water values
Note from the test report (in the German original): Die Werte stammen aus der öffentlichen, live aktualisierten Trinkwasseranalyse-Tabelle der TWA Bad Berka auf der WZV-Weimar-Website (Aktualisierungsstand laut Seite: Juli 2026), abgerufen über die öffentliche Datenschnittstelle der Seite (keine Zugangsdaten, keine Adressabfrage) – kein statisches PDF, aber exakte Tabellenwerte statt einer Zusammenfassung. Die Parameter stammen aus unterschiedlichen Probenahmeterminen: Mikrobiologie/pH/Leitfähigkeit vom 09.06.2026, die meisten chemischen Parameter vom 07.01.2025, Härte/Calcium/Magnesium aus einer separaten Untersuchung vom 02.02.2026. TWA Bad Berka versorgt u. a. den Weimarer Ortsteil Süßenborn (bestätigt durch einen separaten Laborbefund, Prüfbericht Nr. 2535816, Probe vom 20.02.2025). Das Weimarer Stadtgebiet wird jedoch aus einem Verbundsystem mit fünf Aufbereitungsanlagen gespeist (TWA Bad Berka, TWA Tiefengruben, TWA Hohenfelden, WW Heichelheim, WW Sachsenhausen) mit teils deutlich abweichenden Werten – zum Vergleich zeigt WW Sachsenhausen zeitgleich Gesamthärte 22,2 °dH und Nitrat 37,9 mg/l, deutlich höher als hier. Diese Werte gelten also nur für einen Teil des Weimarer Versorgungsgebiets, nicht einheitlich für die ganze Stadt. PFAS wird in dieser Tabelle nicht ausgewiesen und fehlt daher komplett, statt geschätzt zu werden.
Background on household plumbing, not a measurement: in Weimar, 60 % of buildings with living space were built before 1970, and a further 7 % 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 Weimar
- Nitrate 10.3 mg/L – about 21 % of the limit of 50 mg/L and in the medium range – such values occur in catchments shaped by agriculture. Boiling does not reduce nitrate.
- 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 7.94 – 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 Weimar in everyday life
At 13 °dH, Weimar 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 Weimar 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 Weimar 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)
| Substance | Maximum level | Value in Weimar |
|---|---|---|
| Sodium | 20 mg/l | 11.8 mg/l – not above |
| Nitrate | 10 mg/l | 10.3 mg/l – above |
| Nitrite | 0.02 mg/l | below the detection limit (0.005 mg/l) – not above |
| Sulphate | 240 mg/l | 69.5 mg/l – not above |
| Fluoride | 0.7 mg/l | 0.13 mg/l – not above |
| Manganese | 0.05 mg/l | below the detection limit (0.001 mg/l) – not above |
| 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 11.8 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 Weimar
Can you drink the tap water in Weimar?
According to the verified values, yes: All tested parameters with a legal limit (16) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore: 100 out of 100 (data coverage: 6 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 Weimar?
The total hardness is 13 °dH – hardness range “medium”. Dose detergent for the hardness range “medium”.
Is there PFAS in the tap water in Weimar?
The published analysis by WZV Weimar that we evaluated gives no PFAS value. This does not mean there is no PFAS in the water; there is simply no figure for it. Since 12 January 2026, a limit of 0.1 µg/l has applied to the sum of PFAS-20. The supplier can tell you whether PFAS was measured and with what result.
Do I need to filter my tap water in Weimar?
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.
WaterScore
- Total100 / 100
- Chemical safety100 / 100
- Heavy metals100 / 100
- Nutrients100 / 100
- General parameters100 / 100
- Data timeliness100 / 100
- Data quality100 / 100
Data coverage: 6 of 7 core parameters. Not in the test report: PFAS (sum). 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
- Trinkwasseranalysen – Trinkwasseraufbereitungsanlage (TWA) Bad Berka (Wasserversorgungszweckverband Weimar (WZV Weimar))
Suggested citation: Trinkwassermonitor (2026): Tap water in Weimar. Values according to the water supplier’s test report, sampling date July 2026; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/weimar/
JSON: /api/v1/evidence?city=weimar
Data as of: July 2026 · verified: 21 of 21 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 Weimar. Retrieved from https://trinkwassermonitor.ink/en/tap-water/weimar/.”