Support

Rainu starts from the EFSA adequate intake for water from drinks (1,600 ml for women, 2,000 ml for men), then adjusts it for body weight (up to ±500 ml), exercise (about 500 ml per hour), a hot climate (+500 ml), pregnancy (+300 ml) or breastfeeding (+700 ml). The result is rounded to 50 ml and kept between 1,200 and 4,000 ml.

You can see the breakdown and its sources in Rainu's Profile. It's a general estimate for healthy adults: drink to thirst, and follow your doctor's advice if it differs. Read more about the sources.

Coffee is about 99% water, and in moderate amounts it hydrates nearly as well as water. Rainu counts each drink by its typical water content: water and tea 100%, coffee 99%, juice and soda 89%, milk 88%.

Rainu won't suggest coffee or tea in the 6 hours before your bedtime.

Yes. In Profile → Doctor’s advice, choose Daily target from my doctor or Daily maximum (fluid restriction) and enter the amount you were given. Rainu then uses that number instead of its own estimate.

With a daily maximum, Rainu never encourages you to drink more: there are no "drink more" reminders, and it lets you know gently as you get close to your limit. Rainu doesn't give medical advice, so please check any questions about your limit with your healthcare professional.

• Check Settings → Notifications → Rainu and make sure Allow Notifications is on.
• A Focus (Sleep, Work, Do Not Disturb) may be silencing them. Add Rainu to the allowed apps in Settings → Focus.
• If Scheduled Summary is on, reminders may be grouped for later. Set Rainu to Immediate Delivery.
• With Smart reminders on, Rainu skips a reminder when you're already on pace. That's on purpose.
• Reminders stop before bedtime (2 hours by default, adjustable) and are never sent if you've set a daily maximum or chose “Waiting to talk to my doctor”.
• Opening Rainu once refreshes the schedule if your times changed.

Touch and hold an empty spot on your Home Screen, tap Edit → Add Widget, search for Rainu and pick a size. For the Lock Screen, touch and hold the Lock Screen, tap Customize → Lock Screen, then tap the widget area. Widgets also work in StandBy.

You can log a drink straight from the widget, and choose which two amounts it shows in Profile. You can also ask Siri to "Log 250 ml in Rainu".

If a widget looks out of date, open Rainu once and it will refresh.

When you allow it, every drink you log is saved to Apple Health as water, and coffee also adds caffeine. If you undo or delete a drink in Rainu, its Health entry is removed too, so the two stay in step.

Rainu reads only your weight and exercise minutes, to help estimate your goal. It doesn't import water logged by other apps, so nothing gets counted twice.

To change permissions: Settings → Health → Data Access & Devices → Rainu.

In Rainu, go to Profile → Reset data → Reset all data and confirm. This erases your profile, drinks and settings on this iPhone. Deleting the app also removes all its data.

Entries already saved to Apple Health stay there until you delete them in the Health app or in Settings → Health → Data Access & Devices → Rainu → Delete All Data.

We don't hold a copy of your data, so there's nothing for us to delete on our side. See the Privacy Policy.

Yes. Go to Profile → Buttons & units and choose ml or fl oz.

Yes. Rainu 1.0 is free to download and use, with no ads and no in-app purchases.

Not yet. Rainu 1.0 is for iPhone.