Privacy policy

Effective November 14, 2026

H2Oracle is a pool and hot tub water tracker. It’s built to keep your data on your phone: there is no account, no advertising, no analytics and no tracking. This policy covers the H2Oracle app and this website. Questions: support@h2oracle.app.

What stays on your phone

Everything you enter (water tests, chemicals, swims and soaks, upkeep, the names and volumes of your pool and hot tub, reminders and settings) is stored on your phone, and the calculations (doses, predictions, safe to swim) are done on your phone. None of it is sent to us unless you turn on household sync. Uninstalling the app deletes it.

Household sync (optional)

If you turn on household sync to share your log with other phones in your household:

• What’s stored on the sync server: your history, water setup, treatment plans and dismissed predictions, and the name you give each phone. Reminders, reading preferences and the webhook stay on each phone.
• Who can see it: the phones in your household. It’s sent over an encrypted connection (HTTPS) to H2Oracle’s sync server, which we run. It isn’t end-to-end encrypted, so the server can read it; we don’t look at it except to fix a problem you’ve asked us about, and we don’t sell or share it.
• Server log: the server notes when each phone connects and from which internet address, to keep the service running and to stop abuse. The log is kept only as long as it’s needed for that.
• No account: phones join with a single-use invite. We don’t ask for your name, email address or phone number.
• Deleting it: turning sync off on the household’s main phone deletes the household and everything in it from the server. A phone removed from the household stops syncing. You can also email us to have a household deleted.

Webhook (optional)

If you set up a webhook, the app sends each event you log, edit or delete (the event’s details and the name and volume of the pool or hot tub) to the address you enter, such as your own Home Assistant. That goes straight from your phone to that address; we don’t receive it.

Backups

A backup is a file the app makes when you ask it to, holding your log and settings. It goes where you choose to save or send it; we don’t receive it.

Permissions

• Notifications: for the reminders you turn on. They’re scheduled on your phone.
• Internet: only for household sync and the webhook, when you turn them on.
• Local network (iPhone): to reach a webhook on your home network.

The app doesn’t use your location, camera, microphone, contacts or photos.

This website

This website uses no cookies and no analytics. Like any web server, it keeps standard access logs (internet address, page requested, browser) for security.

Children

H2Oracle isn’t directed at children under 13, and we don’t knowingly collect their information.

Changes

If this policy changes, the new version will be posted here with a new date. Significant changes will also be noted in What’s new.