Water hardness and tap water in Oldenburg

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

Oldenburg, Niedersachsen · Postcode 26121, 26122, 26123, 26129, 26131

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 Oldenburg has a total hardness of 12 °dH, hardness range “medium” (as of 14 October 2025). All tested parameters with a legal limit (9) meet the limits set by the German Drinking Water Ordinance (TrinkwV). Source: test report by EWE Netz. WaterScore: 99.9 out of 100 (data coverage: 5 of 7 core parameters).

Limits of the Drinking Water OrdinancemetAll tested parameters (9), at the waterworks
Water hardness12 °dH, mediumNo legal limit, only a range
Data coverageCore parameters: 5 of 7Score based on complete data

Verified drinking-water values

Parameter	Value	Limit (TrinkwV)	Sampling date	Source	Status
Nitrate	4.4 mg/L	50 mg/L	14 October 2025	EWE NETZ GmbH	verified
PFAS (sum)	0.008 µg/L	0.1 µg/L in force since 12 January 2026 from 12 January 2028: additionally PFAS-4 0.02 µg/L	14 October 2025	EWE NETZ GmbH	verified
Lead	< 0.001 mg/L	0.01 mg/L from 12 January 2028: 0.005 mg/L	14 October 2025	EWE NETZ GmbH	verified
Uranium	< 0.001 mg/L	0.01 mg/L	14 October 2025	EWE NETZ GmbH	verified
Copper	0.01 mg/L	2 mg/L	14 October 2025	EWE NETZ GmbH	verified
Chloride	34 mg/L 14 % of the limit	250 mg/L	14 October 2025	EWE NETZ GmbH	verified
Sulphate	57 mg/L 23 % of the limit	250 mg/L	14 October 2025	EWE NETZ GmbH	verified
Sodium	19 mg/L	200 mg/L	14 October 2025	EWE NETZ GmbH	verified
Calcium	73 mg/L	–	14 October 2025	EWE NETZ GmbH	verified
Magnesium	7.7 mg/L	–	14 October 2025	EWE NETZ GmbH	verified
pH	7.4	6.5–9.5	14 October 2025	EWE NETZ GmbH	verified
Total hardness	12 °dH (medium)	no legal limit	14 October 2025	EWE NETZ GmbH	verified
Electrical conductivity	470 µS/cm	–	14 October 2025	EWE NETZ GmbH	verified

Note from the test report (in the German original): EWE NETZ GmbH · Prüfbericht P259206 (Probenahme 14.10.2025), Zone Alexanderfeld. Oldenburg hat mindestens zwei weitere geprüfte Zonen: Sandkrug (weicher: 6,6 °dH, PFAS unterhalb Bestimmungsgrenze, Probe 14.10.2025) und Donnerschwee (Wasserwerksausgang, Nitrat 11 mg/l, PFAS-20 nur 1,0 ng/l, Probe 12.03.2025). Alle drei Zonen liegen im Versorgungsgebiet V403V0001.

Is a value wrong or out of date?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 Oldenburg, 42 % of buildings with living space were built before 1970, and a further 14 % 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 Oldenburg

Nitrate 4.4 mg/L – about 9 % of the limit of 50 mg/L and in the unremarkable range. Boiling does not reduce nitrate.
PFAS (sum of PFAS-20) 8 ng/L – about 8 % 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 – not detectable at the waterworks (limit 10 µg/L).
pH 7.4 – 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 Oldenburg in everyday life

At 12 °dH, Oldenburg 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 Oldenburg 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 Oldenburg 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 Oldenburg
Sodium	20 mg/l	19 mg/l – not above
Nitrate	10 mg/l	4.4 mg/l – not above
Nitrite	0.02 mg/l	not in the report
Sulphate	240 mg/l	57 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	not in the report
Uranium	0.002 mg/l	below the detection limit (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 19 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 Oldenburg

Can you drink the tap water in Oldenburg?

According to the verified values, yes: All tested parameters with a legal limit (9) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore: 99.9 out of 100 (data coverage: 5 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 Oldenburg?

The total hardness is 12 °dH – hardness range “medium”. Dose detergent for the hardness range “medium”.

Is there PFAS in the tap water in Oldenburg?

Yes, in measurable amounts: according to the published analysis by EWE Netz (as of 14 October 2025), the sum of PFAS-20 is 0.008 µg/l – that is 8 % of the limit of 0.1 µg/l, which has applied since 12 January 2026. Even this sum of all 20 substances is below the limit of 0.02 µg/l that applies from 12 January 2028 to the sum of four of them (PFAS-4).

Do I need to filter my tap water in Oldenburg?

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

Total99.9 / 100
Chemical safety100 / 100
Heavy metals100 / 100
PFAS100 / 100
Nutrients100 / 100
General parameters100 / 100
Data timeliness99.6 / 100
Data quality100 / 100

Data coverage: 5 of 7 core parameters. Not in the test report: Nitrite and Arsenic. 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 Oldenburg, Zone Alexanderfeld, Probenahme 14.10.2025 (EWE NETZ GmbH) · SHA-256 of the evaluated file: 69c6f3c8188ea90d…, checked on 3 October 2026

Suggested citation: Trinkwassermonitor (2025): Tap water in Oldenburg. Values according to the water supplier’s test report, sampling date 14 October 2025; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/oldenburg/

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

Data as of: 14 October 2025 · verified: 13 of 13 evaluated parameters. (older than twelve months – under § 46 TrinkwV your supplier must publish current values online)

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 Oldenburg. Retrieved from https://trinkwassermonitor.ink/en/tap-water/oldenburg/.”