Fastio

Q: Is Fastio alkaline?

Fastio has a published pH of 6, which is slightly acidic (7 is neutral).

Q: How much sodium (salt) is in Fastio?

Fastio has 4.1 mg/L of sodium, as published. That is under 20 mg/L, the UK/EU level for “suitable for a low-sodium diet”.

Q: Does Fastio have electrolytes?

Its published analysis lists, per litre: calcium 1.3 mg/L, sodium 4.1 mg/L, potassium 0.6 mg/L, bicarbonate 8 mg/L, chloride 4.2 mg/L and sulfate 1 mg/L.

Q: Is Fastio spring, mineral or purified water?

Fastio is a still natural mineral water.

Fastio is a very low-mineral Portuguese natural mineral water from the Gerês mountains, classed as hyposaline and silicated. — as described by the brand

7.5/107/9 properties published

pH6 ideal 6.5–8.56.8
TDS34 mg/L ideal 225–500 mg/L5.0
Sodium4.1 mg/L ideal up to 20 mg/L10.0
Calcium1.3 mg/L ideal 36.7–80 mg/L · counts half5.0
MagnesiumNot published −0.1—
Sulfate1 mg/L ideal up to 248 mg/L10.0
Chloride4.2 mg/L ideal up to 250 mg/L10.0
NitrateNot published −0.1—
Bicarbonate8 mg/L ideal 30–396.6 mg/L · counts half5.0

Each bar is out of 10 for that property. Deductions: −0.2 for missing values, −0.1 for an undated analysis. Editorial score, not a health rating. How scores work →

How it stands out

Sodium is 4.1 mg/L, under the 20 mg/L level the UK/EU uses for “suitable for a low-sodium diet” on natural mineral water labels.

Taste notes

No taste notes yet. Soon you will be able to say how Fastio tastes to you. Results will appear here once people have voted; nothing is shown until then.

SoftNo votes
CrispNo votes
SmoothNo votes
MineralNo votes
SaltyNo votes
SweetNo votes
BitterNo votes
MetallicNo votes

Ratings & reviews

Waterphile Score lab data

7.5/10

From the brand’s published mineral values. How it works

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Similar waters

Computed from published numbers only: the waters whose mineral values are closest to Fastio’s on a log scale, using the values both brands publish as single numbers (at least 5). pH and nitrate are not used. Similar minerals do not mean similar taste.

Source & spring

Source	Nascente N.ª Sr.ª do Fastio, Chamoim, Terras de Bouro (Serra do Gerês), Portugal
Country	Portugal · all waters from Portugal
Water type	Natural mineral water · what this means
Still or sparkling	Still
Data source	Fastio 1 L label composition as published by retailer Auchan Portugal (undated); cross-check DGEG Hidrogenoma registry Last checked 2026-10-29

Fastio ingredients & nutrition facts

per litre

FastioPer litre · 9 of 11 values published

Basics

Total dissolved solids dry residue 180°C

34 mg/L

Minerals

Calcium

1.3 mg/L

Magnesium

—

Sodium

4.1 mg/L

Potassium

0.6 mg/L

Other dissolved substances

Bicarbonate

8 mg/L

Sulfate

1 mg/L

Chloride

4.2 mg/L

Nitrate (NO₃)

—

Silica

9.6 mg/L

— Not published by the brand · we never estimateSource: Fastio 1 L label composition as published by retailer Auchan Portugal (undated); cross-check DGEG Hidrogenoma registry · checked 2026-10-29

Label (via Auchan): dry residue 180 °C 34.0 ± 4, SiO2 9.6, pH (18 °C) 6.0, HCO3 8.0, Cl 4.2, SO4 1.0, Na 4.1, Ca 1.3, K 0.6 mg/L; magnesium not listed. Government registry DGEG Hidrogenoma (https://hidrogenoma.dgeg.gov.pt/agua-mineral-natural/agua-do-fastio): full analysis 27/04/2016, total mineralisation 41 mg/L, pH 6.1, 34 µS/cm; hyposaline, silicated.

UK/EU label thresholds met

Applied to the published numbers for information; these indications legally apply to natural mineral water labels.

Very low mineral content (fixed residue ≤ 50 mg/L)
Suitable for a low-sodium diet (sodium < 20 mg/L)

Brands update their analyses from time to time, and values can differ between bottle sizes, plants and batches. Check the label on your bottle. Spotted a change? See corrections.

Fastio FAQ

Is Fastio alkaline?

Fastio has a published pH of 6, which is slightly acidic (7 is neutral).

How much sodium (salt) is in Fastio?

Fastio has 4.1 mg/L of sodium, as published. That is under 20 mg/L, the UK/EU level for “suitable for a low-sodium diet”.

Does Fastio have electrolytes?

Its published analysis lists, per litre: calcium 1.3 mg/L, sodium 4.1 mg/L, potassium 0.6 mg/L, bicarbonate 8 mg/L, chloride 4.2 mg/L and sulfate 1 mg/L.

Is Fastio spring, mineral or purified water?

Fastio is a still natural mineral water.

Where does Fastio come from?

Nascente N.ª Sr.ª do Fastio, Chamoim, Terras de Bouro (Serra do Gerês), Portugal.

Where to buy

See the official Fastio website for stockists. Retailer and price links are coming later.

Compare Fastio with

Not medical advice. Waterphile shows mineral values as published by each brand, for general information only. If you have a health condition, follow a restricted diet or prepare infant formula, ask a doctor, pediatrician or health visitor.