Tap Water

Why tap water is rated low

Tap water is low FODMAP at Any typical portion, with the rating estimated from what it is made of rather than a measured serving. That estimate is about as simple as they come: plain water carries no carbohydrate at all, so there is nothing in the glass for a FODMAP rating to count. Where water stops being a straightforward low is when something else goes into it, and that is where the rest of this page focuses.

What changes your risk

• What you stir into it Cordial, squash, drink mixes and flavour drops can be sweetened with high fructose corn syrup, honey, agave syrup or sugar-free sweeteners that are not low FODMAP. The drink then takes the rating of whatever was added.
• Flavoured and enhanced waters Bottled vitamin waters, fruit waters and sports drinks are not plain water. Their sweeteners and fruit juice concentrates can carry a FODMAP load that tap water does not.
• What you brew with it Water used for a stock cube, soup base or instant gravy takes on whatever is in the powder, and those often hide onion and garlic.
• Cooking water Boiling does not destroy FODMAPs, but some FODMAPs dissolve in water, so they can leach out of vegetables and legumes into the pot. The liquid left after boiling onion or legumes is no longer the plain water that went in.
• The rest of the meal Water adds nothing to a meal's FODMAP total and takes nothing away either. Drinking plenty alongside a high FODMAP meal does not dilute what is on the plate.

What else works

Filtered water, still or sparkling mineral water and plain soda water sit in the same place as tap water when nothing has been added to them. The lookalikes that are not the same thing are flavoured waters, vitamin waters, sports drinks and cordial concentrates, which often carry high fructose corn syrup, fruit juice concentrate or sugar-free sweeteners. To flavour water without changing its story, use fresh orange, strawberries or cucumber rather than a bottled flavouring.

How to keep it low

For FODMAP purposes, tap water needs no portioning; the low rating is about FODMAPs only, and how much water to drink in a day is a separate question. The useful habit is making flavoured water yourself: drop orange, strawberries or cucumber into a jug in the fridge instead of buying a flavoured bottle. If you do buy bottled water, check that the ingredient list reads only water and minerals, since anything with a sweetener or juice concentrate is a different product. When making tea, coffee or a broth, the water is fine and the question moves to what goes in with it.

Common questions

is tap water low fodmap

Yes. Tap water is rated low FODMAP at Any typical portion, estimated from what it is made of: it has no carbohydrate for a FODMAP rating to count.

is flavored water low fodmap

Not automatically. Flavoured and vitamin waters can carry high fructose corn syrup, fruit juice concentrate or sugar-free sweeteners, so read the ingredient list, because plain water is the only one this rating covers.

can i drink water on the low fodmap elimination phase

Yes. Plain tap water fits every phase of the diet, and it is a reliable base for tea, coffee and homemade drinks as long as you watch what you add.

is sparkling water low fodmap too

Plain sparkling or soda water with nothing but water and gas has no carbohydrate either, so it follows the same logic as tap water. Flavoured sparkling waters need their labels checked.