Last updated: September 17, 2026
These Terms of Service ("Terms") govern your access to and use of the Hydrolitica website at hydrolitica.com, including its simulation engine, calculators, documentation, articles and related services (together, the "Platform"). By accessing or using the Platform you agree to these Terms. If you do not agree, do not use the Platform.
Hydrolitica is operated by Teachers AI Éxito LLC, 30 N Gould St, Sheridan, WY 82801, USA, a limited liability company ("we", "us", "our"). You can reach us at info@hydrolitica.com or through the contact page.
Hydrolitica is an independent product. It implements published water-quality modeling methods, including those of the QUAL2K and QUAL2Kw models. It is not affiliated with, endorsed by or sponsored by the US Environmental Protection Agency (EPA), Tufts University, the Washington State Department of Ecology or any other government body, environmental authority or university. Names of models, agencies and institutions are used only to describe the methods and data formats the Platform works with.
By creating an account, running a simulation, using a calculator or making a payment, you confirm that you have read and accept these Terms, our Privacy Policy and our Refund and Cancellation Policy. If you use the Platform for an organization, you confirm that you may bind that organization to these Terms.
The Platform provides, among other things:
Features may change over time. We may add, modify or remove features, and we will not reduce what a paid plan includes during a period you have already paid for.
Results are model estimates. Check them before you rely on them.
4.1 Estimates that depend on your inputs. Simulation outputs and calculator results are numerical estimates. They depend on the data, parameters and assumptions you enter and on the simplifications inherent in any water-quality model. Different inputs, calibration choices or software can give different results.
4.2 Content may contain errors. Results, calculations, documentation, articles, AI-generated responses, example data, prices and other content on the Platform may contain errors or be out of date. We test the engine against reference models, but we do not promise that any result is accurate, complete or suitable for a particular purpose.
4.3 Not professional advice or regulatory approval. The Platform is a computational tool. It does not replace professional engineering judgement, a qualified modeler's review, laboratory data or the approval of any environmental authority. Nothing on the Platform is an official source, and using it does not guarantee any outcome, such as a permit, a license, the acceptance of a study by an authority or compliance with any regulation.
4.4 Your responsibility. You use the Platform at your own risk. Before using results for environmental assessments, permit applications, engineering designs, public-health or other important decisions, verify them independently and have them reviewed by qualified professionals, and check the official sources that apply to your case.
5.1 Free use. You can use the engine and the calculators a limited number of times without an account, and a further number of times each month with a free account. The current limits are shown on the pricing page and in the app, and we may change them.
5.2 Hydrolitica Pro. Hydrolitica Pro is a paid subscription that removes the monthly limits. It costs USD 19 per month or USD 149 per year, charged in US dollars (USD) by our payment processor, Stripe. Your bank may add currency conversion or foreign transaction fees. Taxes, if any apply, are shown at checkout. The price and billing period you accept at checkout are the ones that apply to your subscription.
5.3 Automatic renewal. Your subscription renews automatically at the end of each billing period (every month for the monthly plan, every year for the annual plan), and the payment method on file is charged the price of your plan until you cancel. If a renewal payment fails, Pro features may be paused until the payment succeeds.
5.4 How to cancel. You can cancel at any time. Sign in, open the account menu (top right) and choose Manage subscription, which opens the Stripe customer portal where you can cancel, change your card and download invoices. You can also ask us to cancel by writing to info@hydrolitica.com or through the contact page. Cancellation stops future renewals. You keep Pro access until the end of the billing period you have already paid for, and no further charges are made.
5.5 Price changes. If we change the price of a plan, we will tell you before the change applies to your subscription, and the new price will only apply from your next renewal. You can cancel before that renewal.
All purchases are final and non-refundable.
Because access to the paid digital service is granted immediately after payment, payments are non-refundable, including for partially used or unused billing periods, and a plan cannot be cancelled for a refund. Cancelling stops future renewals as described in section 5.4. This does not limit any right that the mandatory consumer-protection law of your country grants and that cannot be waived.
If you see a duplicate or unauthorized charge, or any other billing error, write to info@hydrolitica.com (or use the contact page) and we will correct it. Full details are in our Refund and Cancellation Policy.
7.1 What it is. We may give Pro-level access at no cost to students and staff of educational institutions that we have registered. Eligibility is based on a verified email address with the registered institution's domain.
7.2 Registration. Institutions can apply through the Platform. We review applications at our discretion and may end a registration at any time.
7.3 Use. University Premium access is for teaching and research. Commercial use under this program needs our prior written permission.
8.1 Your account. Some features need an account. Give accurate information and keep it up to date.
8.2 Security. Keep your sign-in credentials confidential. You are responsible for activity under your account. Tell us at info@hydrolitica.com if you suspect unauthorized use.
8.3 Suspension. We may suspend or close an account that breaks these Terms or the law, or that puts the Platform or other users at risk.
You agree not to:
10.1 The Platform. The Platform's software, design, text and graphics belong to us or our licensors and are protected by intellectual property laws. These Terms do not give you any right to use our names or logos. Third-party names and trademarks mentioned on the Platform belong to their owners and are used only to describe compatibility or sources; no endorsement is implied. For example, Excel is a trademark of Microsoft Corporation and ISO is a registered trademark of the International Organization for Standardization.
10.2 Your data. You keep ownership of the data you enter and the projects you create. You give us a limited license to process that data only to provide the service to you.
How we collect and use personal data is described in our Privacy Policy. Project data and results are stored on Google Cloud (Firebase). We use reasonable security measures, but no system is completely secure.
TO THE EXTENT THE LAW ALLOWS, THE PLATFORM IS PROVIDED "AS IS" AND "AS AVAILABLE", WITHOUT WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT AND ACCURACY. WE DO NOT WARRANT THAT THE PLATFORM WILL BE UNINTERRUPTED OR ERROR-FREE, OR THAT ITS RESULTS WILL BE ACCURATE OR RELIABLE.
TO THE EXTENT THE LAW ALLOWS, WE ARE NOT LIABLE FOR INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL OR PUNITIVE DAMAGES, OR FOR LOSS OF PROFITS, REVENUE, DATA OR GOODWILL, ARISING FROM YOUR USE OF OR INABILITY TO USE THE PLATFORM OR FROM DECISIONS BASED ON ITS RESULTS. OUR TOTAL LIABILITY FOR ALL CLAIMS RELATED TO THE PLATFORM OR THESE TERMS IS LIMITED TO THE AMOUNT YOU PAID US IN THE 12 MONTHS BEFORE THE CLAIM.
You agree to indemnify and hold us harmless from claims, losses and costs (including reasonable legal fees) arising from your misuse of the Platform, your breach of these Terms or the law, decisions or submissions you make based on Platform results, or your infringement of anyone else's rights.
We may update these Terms. When a change is material we will give notice on the Platform. The date at the top shows the latest version. If you keep using the Platform after a change takes effect, the updated Terms apply to you.
These Terms are governed by the laws of the State of Wyoming, USA, where the operator is registered, without regard to conflict-of-law rules. Disputes will be resolved by binding individual arbitration, not as a class or representative action, unless the mandatory law of your country gives you the right to go to your local courts.
If a provision of these Terms is found unenforceable, the rest remains in effect and that provision is applied to the extent it can be. These Terms, the Privacy Policy and the Refund and Cancellation Policy are the entire agreement between you and us about the Platform.
Teachers AI Éxito LLC
30 N Gould St
Sheridan, WY 82801
USA
Email: info@hydrolitica.com
Contact form: hydrolitica.com/contact