Invited pilot · not final

Pilot terms

Version pilot-1 · September 20, 2026, operating company corrected September 22, 2026 · accepted when you create an account

This is short on purpose. It is a pilot agreement, written to be read in five minutes and to say only what is true today, and it is the agreement in force. A fuller one is being prepared and reviewed; when it is ready it replaces this, and you will be asked to accept it rather than being moved onto it quietly.

1 Who this is between

You, or the organization you are signing up on behalf of, and CZDTS LLC, a limited liability company, whose mailing address is 4539 N 22nd St #5089, Phoenix, AZ 85016, USA, and which operates CurveNumber. "We" and "us" mean that entity. "You" means the account holder.

If you are creating an account for an employer or a client, you are confirming that you may accept these terms on their behalf.

Until September 22, 2026 this section named a different company. The product is now operated by CZDTS LLC and nothing in it is operated by the previous entity. The version is still pilot-1. When the questions below are answered, the terms get a new version and every pilot account is asked to accept it, as section 8 says.

[To be completed after legal review: the state CZDTS LLC is organized in, the law that governs this agreement, and the courts that hear a dispute under it.]

2 What you are getting, and what it is not

CurveNumber computes stormwater runoff and green infrastructure reduction from public datasets and from figures you supply, and records where every figure came from. It is a calculation and record-keeping tool.

It is not engineering, it is not a professional opinion, and it is not a substitute for one. It does not know the intent of your jurisdiction's requirements. It cannot tell you whether a design is adequate, and it is built so that it will not try. Local law may require a licensed professional to review the work whatever any tool produces.

Where the software declines to produce a figure, that refusal is part of what you are paying for and not a fault. Overruling one is something you may do, in writing, under your own name, and the record keeps both the refusal and your reason.

3 What is unfinished, stated plainly

This is pre-launch software and you are an invited pilot user. We would rather tell you the following now than have you discover it in a review:

• The published curve number tables and rainfall distributions in this engine were transcribed by one person and have not been independently checked. The software records that fact and prints it beside the citation rather than implying otherwise. The cover table shipped is a 22 row subset of TR-55 Tables 2-2a to 2-2d.
• Fifty-four of the one hundred twenty-six default values state on their face that no external source exists for them. Seven more state that a source exists and was not checked.
• The site peak discharge uses unit hydrograph and rainfall distribution tables that are among those not yet independently checked.
• Coverage is the contiguous United States (the lower 48 states), because the public datasets are.
• Features exist in the software that are switched off, and the About page lists them.

The technical white paper and the source coverage register go further than this section does, and neither is marketing.

4 Your account

Keep your password and your API keys to yourself; anything done with them is treated as done by you. Tell us promptly if you think either has been exposed. One person, one account: do not share a login.

You may close your account at any time from the account screen. Closing signs out every browser and revokes every API key, and deletes nothing: your projects, sites, runs, reports and audit trail stay where they are and the account can be reopened. If you want data deleted rather than retained, write to us and say so.

5 What you pay during the pilot

There is no subscription. Every new account gets two free site codes, each good for about two months. After that, USD 100 opens a 30-day working window on one site, and USD 20 adds 30 more days to it. A site is paid for when it is first computed, not when it is created, and within its window you can compute it as often as you need. After the window closes, its reports and published versions stay available; computing it again needs the window re-opened. Each site includes USD 20 of AI assistant use, with more in USD 5 top-ups. Payment is by invoice until card payment is available. The pricing page has the current figures.

During the invited pilot nothing is charged at all, the free allowance is not consumed, and the billing screens are hidden rather than left to imply a transaction that is not happening. If that changes you will be told before it does, not after.

6 Your data

Your site boundaries, figures and reports are yours. We do not sell them, and we do not use them to train anything.

To derive anything at all, the software sends your site boundary to public data services run by agencies of the United States government, and sends an address you type into the search box to the Census Bureau. The map draws itself from USGS directly in your browser. The privacy notice lists each service and exactly what reaches it. If the existence of your interest in a parcel is itself confidential, read that section before you derive.

If the optional assistant is switched on for your account, your site record is sent to a commercial model vendor with email addresses replaced and the site address and client name withheld. That is pseudonymization and not anonymization, and the privacy notice says so.

7 No warranty, and the limit of our liability

The software is provided as is. We do not warrant that it is free of defects, that it will be available, that the public datasets it reads are correct or current, or that any figure it produces is fit for any particular purpose. You have read section 3.

To the fullest extent the law allows, our total liability to you for anything arising out of your use of CurveNumber is limited to the amount you have actually paid us in the twelve months before the claim, which during the pilot is zero. We are not liable for loss of profit, loss of a contract, the cost of redesign, or any indirect or consequential loss.

Nothing here limits liability that cannot lawfully be limited.

You are responsible for your use of what the software produces, including any design you seal and any submission you make. If a claim is brought against us because of a design you produced, you will cover our reasonable costs in dealing with it.

8 Ending it, and changing this

You can stop using CurveNumber whenever you like. We can end a pilot account with reasonable notice, and immediately if an account is being used to attack the service or break the law.

These terms carry a version, and this one is pilot-1. When they change, the new version gets a new identifier and you will be asked to accept it. We will not treat continued use as agreement to a document you have not seen.

[To be completed after legal review: the governing law and the courts that hear a dispute, as in section 1.]

Notices to us go to support@curvenumber.com, or by post to CZDTS LLC, 4539 N 22nd St #5089, Phoenix, AZ 85016, USA. That postal address is the one we have given for mail; it is not a statement about where the company is organized, which is the first part of the question in section 1.

A fuller agreement is being prepared with counsel. It is not published and not in force; this page is the one that binds.