Celtic Spring
Own brand of Montgomery Waters, the bottler at Churchstoke, Powys, drawing on the site since 1998. Defra’s register lists the trade description twice, for two sources there: “CS1” and “Silverbrook Falls”. The names have moved: a 2007 Gazette notice renamed Offa’s Spring as CS1, and a 2011 notice swapped the Celtic Spring and Silverbrook Falls names between two boreholes. The producer describes deep boreholes in fractured volcanic rock near Offa’s Dyke. Montgomery Waters Ltd is controlled by Delfin Investments Ltd, whose ultimate owner is Gilroy Donald Delves MBE (Companies House, notified April 2016). The same site bottles Belu and own-label water for retailers including Booths, Tesco, Co-op and Spar. The producer doesn’t say which borehole supplies which.
Mineral composition
| mg/L | |
|---|---|
| Calcium | 49 |
| Magnesium | 7 |
| Sodium | 12 |
| Sulfate | 21 |
| Chloride | 21 |
| Bicarbonate | awaiting data |
Mineral data incomplete — check the label for full composition.
Compositions can vary by season and source. Read our methodology.
Mineral character
Moderately hard. Per litre: calcium 49.3 mg, magnesium 6.5 mg, sodium 11.7 mg, sulphate 20.7 mg, chloride 21.0 mg. Hardness is about 150 mg/L as CaCO₃, dry residue 234 mg/L, pH 7.96. Bicarbonate isn’t published, so the profile is incomplete. The analysis doesn’t say which of the two registered sources it describes. It differs from Belu’s on every ion, so they are not the same borehole.
Use-case suitability
- CoffeeNot used in any current coffee recipe, but hardness 150 mg/L sits within the 9–266 mg/L range typical for these targets.
- TeaNot used in any current tea recipe. Hardness 150 mg/L is above the 37–59 mg/L range of these targets.
- BrewingNot used in any current brewing recipe, but hardness 150 mg/L sits within the 26–922 mg/L range typical for these targets.
- BakingNot used in any current baking recipe, but hardness 150 mg/L sits within the 46–390 mg/L range typical for these targets.
- AquariumNot used in any current aquarium recipe, but hardness 150 mg/L sits within the 35–212 mg/L range typical for these targets.
- HorticultureNot used in any current horticulture recipe. Hardness 150 mg/L is above the 12–54 mg/L range of these targets.
Where to buy
UK
Not found online (producer says 'retailers nationwide', none named)
The producer says retailers stock it nationwide, plain, sparkling and flavoured, but names none. We found no retailer listing or price on 13 October 2026.