Privacy Policy

Last updated: September 17, 2026

This policy explains how Hydrolitica (hydrolitica.com) handles personal data. We collect only what we need to run the service, we do not sell personal data, and we disabled advertising personalization signals on our Google Ads tag.

1. Who is responsible

The data controller is Teachers AI Éxito LLC, 30 N Gould St, Sheridan, WY 82801, USA:

Teachers AI Éxito LLC
30 N Gould St
Sheridan, WY 82801
USA
Email: info@hydrolitica.com
Contact: hydrolitica.com/contact

2. What we collect

Account data: when you sign in with Google (or with email and password), we receive your name, email address, profile photo and a user ID from Firebase Authentication.
Your models and results: river, reach, source, rate and weather data you enter, simulation results and saved projects. Without an account, your model is sent to our servers only to compute the results and is not saved there (apart from limited technical logs); your draft stays in your browser.
Usage counters: how many free simulations and calculator uses you have made. Without an account this counter is kept in your browser.
Payment data: payments are processed by Stripe. We receive your Stripe customer ID, subscription status, plan and billing email. We never see or store your full card number.
Messages you send us: emails you send to our address, the text of contact messages and error reports, the email address you give us for the reply, the page address, browser, screen size and, if you are signed in, your user ID and email.
Technical data: IP address, browser and device information and request logs, used to run and secure the service (for example to rate-limit the AI assistant and PDF generation).
Analytics and advertising data: see section 5.

3. How we use it

To provide the service: sign-in, running simulations and calculators, saving projects, generating reports
To manage subscriptions, billing, cancellations and billing questions
To answer your messages and fix reported problems
To keep the service secure and prevent abuse
To understand how the site is used and improve it
To measure whether our ads lead to sign-ups and purchases
To send service emails, such as a welcome message, payment confirmations and payment problems (we do not send marketing newsletters)

Where the law requires a legal basis, we rely on performing our contract with you (the service and billing), our legitimate interests (security, product improvement and measuring our advertising), your consent where it is required, and legal obligations (for example keeping billing records).

4. Who we share it with

We share personal data only with providers that help us run the service, and only for that purpose:

Google Cloud and Firebase (Google LLC): hosting, sign-in, database, cloud functions and analytics
Stripe: payment processing and the customer portal
Brevo: delivery of service emails
Cloudflare: routing of email sent to our address
Google Gemini API: if you use the AI assistant, the text you send it and the model context it needs are processed by Google to generate the answer
Open-Meteo: if you use the weather auto-fill, the coordinates and dates of your site are sent to Open-Meteo from your browser
Content delivery networks (for example jsDelivr and Google static content servers) that serve fonts, styles and images, which see your IP address

We may also disclose data when the law requires it, or to protect our rights and the safety of users.

5. Cookies, analytics and advertising

We use Google Analytics (through Firebase) to count visits and understand how pages are used, and the Google Ads tag (gtag.js) to measure visits that come from our ads and two conversions: creating an account and buying a subscription. When you buy, the conversion includes the amount paid and an order ID, never your card details. We turned off advertising personalization signals on the Google Ads tag, and in the European Economic Area, the United Kingdom and Switzerland the tag starts with advertising storage denied. These tools use cookies and similar identifiers. You can block or delete cookies in your browser settings, and learn more about how Google uses data at policies.google.com/technologies/partner-sites.

We also use your browser's local storage for things you would expect: your theme and language, unsaved drafts, free-use counters and markers that stop a conversion from being counted twice.

6. How long we keep data

Account data, projects and results: while your account is active, and until you ask us to delete them
Billing records: as long as tax and accounting laws require
Messages and error reports: as long as needed to handle them
Backups and logs may keep copies for a limited time before they are overwritten

7. International transfers

We are based in the United States and our providers may process data in the United States and other countries. Where the law requires it, we rely on the safeguards our providers offer for these transfers.

8. Your rights

Depending on where you live, you may have the right to access, correct, delete or export your personal data, to object to or restrict some uses, and to withdraw consent. To exercise any of these rights, write to info@hydrolitica.com (or use the contact page) from the email address of your account. We may need to confirm your identity. You can also complain to your local data protection authority.

9. Security

We use access controls, encrypted connections and per-user data rules to protect your data. No online service is completely secure, so we cannot guarantee absolute security.

10. Children

Hydrolitica is a professional and academic tool and is not directed to children under 16. We do not knowingly collect their personal data.

11. Changes

We may update this policy. The date at the top shows the current version, and we will give notice on the site when a change is material.

12. Contact

Teachers AI Éxito LLC
30 N Gould St
Sheridan, WY 82801
USA
Email: info@hydrolitica.com
Contact form: hydrolitica.com/contact