Water hardness and tap water in Bornheim
Rhein-Sieg-Kreis, Nordrhein-Westfalen · Postcode 53332
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 (7), at the waterworks
- Water hardness12 °dH, mediumNo legal limit, only a range
- Data coverageCore parameters: 3 of 7Score provisional
Verified drinking-water values
Note from the test report (in the German original): StadtBetrieb Bornheim AöR · Prüfbericht PB2607088 des Instituts für Hygiene und Öffentliche Gesundheit Bonn, Proben vom 15.06.2026. Der StadtBetrieb versorgt laut eigener Seite das Stadtgebiet Bornheim aus dem Wasserwerk Eichenkamp, ausgenommen die Coloniastraße in Walberberg (Stadtwerke Brühl). Das Werk mischt Wasser zweier Vorlieferanten (Eingang WTV 6,1 °dH, Eingang WBV 17 °dH); übernommen ist die Probe am Werksausgang (12 °dH). Die Netzproben in den Ortsteilen zeigen am selben Tag 10 bis 12 °dH, je nach Mischung. Uran und Blei stammen aus der Netzprobe am Rathaus, weil der Bericht sie nur dort nennt. Einen PFAS-Wert enthält der Bericht nicht; laut StadtBetrieb messen das die Vorlieferanten.
Background on household plumbing, not a measurement: in Bornheim, 39 % 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 Bornheim
- Nitrate 19 mg/L – about 38 % 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 0.38 µg/L – unremarkable against a limit of 10 µg/L. In some regions uranium occurs naturally from the rock (geogenic).
- pH 7.5 – 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 Bornheim in everyday life
At 12 °dH, Bornheim 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 Bornheim 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 Bornheim 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 Bornheim |
|---|---|---|
| Sodium | 20 mg/l | 32 mg/l – above |
| Nitrate | 10 mg/l | 19 mg/l – above |
| Nitrite | 0.02 mg/l | not in the report |
| Sulphate | 240 mg/l | 55 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 | 0.00038 mg/l – not above |
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 Bornheim
Can you drink the tap water in Bornheim?
According to the verified values, yes: All tested parameters with a legal limit (7) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore (provisional): 100 out of 100 – the test report contains only 3 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 Bornheim?
The total hardness is 12 °dH – hardness range “medium”. Dose detergent for the hardness range “medium”.
Is there PFAS in the tap water in Bornheim?
The published analysis by StadtBetrieb Bornheim 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 Bornheim?
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
- Total (provisional)100 / 100
- Chemical safety100 / 100
- Heavy metals100 / 100
- Nutrients100 / 100
- General parameters100 / 100
- Data timeliness100 / 100
- Data quality100 / 100
Data coverage: 3 of 7 core parameters. Not in the test report: Nitrite, Copper, Arsenic and PFAS (sum). Missing parameters are neither estimated nor counted as harmless: the score is based only on the values available and is therefore provisional. 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
- Prüfbericht PB2607088 – Netzproben Wasserwerk der Stadt Bornheim, Probenahme 15.06.2026 (StadtBetrieb Bornheim AöR (Prüfbericht Institut für Hygiene und Öffentliche Gesundheit, Universitätsklinikum Bonn)) · SHA-256 of the evaluated file: c238917376f844fe…, checked on 19 October 2026
Suggested citation: Trinkwassermonitor (2026): Tap water in Bornheim. Values according to the water supplier’s test report, sampling date 15 June 2026; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/bornheim/
JSON: /api/v1/evidence?city=bornheim
Data as of: 15 June 2026 · verified: 11 of 11 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 Bornheim. Retrieved from https://trinkwassermonitor.ink/en/tap-water/bornheim/.”