Terms of Use

Last updated: 31 July 2026

1. About these terms

These Terms of Use (the Terms) govern your access to and use of the Watercalcs website and the calculators, tools, and related services available through it (the Service). The Service is provided by Water Software Solutions Ltd, trading as Watercalcs (we, us, our). By accessing or using the Service, you agree to these Terms. If you do not agree, you must not use the Service.

Where a subscription covers more than one person under a single organisation account, clause 14 (Team Plans) applies in addition to the rest of these Terms.

2. The Service

Watercalcs provides online engineering calculators and related tools for water treatment. Basic calculators are available free of charge. Certain advanced features are available only on a paid subscription (Premium).

The Service is a suite that changes over time. We may add, modify, replace, or withdraw individual calculators, tools, and features at any time. A subscription is to the Service as a whole, and not to any particular calculator, tool, or feature. We do not guarantee that any specific calculator, tool, or feature will remain available, and its withdrawal is not a breach of these Terms.

3. Professional use and your responsibility

The Service is intended for use by suitably qualified and experienced professionals. The calculators produce estimates and indicative results based on the inputs you provide and on published methods and models. They are tools to support your own professional judgement, not a replacement for it. You are responsible for the inputs you enter, for checking the outputs, and for any decisions you make. Please read section 8 (Limitations of use and disclaimer), which sets out important limitations on the outputs.

4. Accounts

You do not need an account to use the free calculators. To subscribe to Premium you must create an account. You agree to provide accurate information, to keep your login details secure, and to be responsible for activity under your account. Notify us promptly of any unauthorised use.

Accounts are personal to the individual who holds them. Login details must not be shared. Where access is provided through a Team Plan, clause 14 sets out how that access works.

5. Subscriptions, billing, and cancellation

Premium is offered on a recurring subscription. Payment is processed by our payment provider, Stripe; we do not store your full card details. Subscriptions renew automatically each billing period until cancelled. You may cancel at any time, effective at the end of the current paid period; unless required by law or expressly provided in clause 13, fees already paid are non-refundable.

Tax. All prices are stated excluding applicable taxes. Tax is calculated and applied at checkout, or shown on the invoice, according to your location and status, and may include New Zealand GST.

Changes to pricing. We may change our subscription pricing, and may change or introduce new subscription plans, tiers, or billing periods. We will give you at least 30 days’ notice of any price increase affecting your subscription, by email to the address on your account or by notice within the Service. A price change takes effect from your next renewal after the notice period; it does not change the price of a billing period you have already paid for. If you do not accept the new price, you may cancel before your next renewal, and your subscription will end at the close of your current paid period. Continuing to use Premium after the change takes effect means you accept the new price.

Where the subscription is a Team Plan, notice of a price change will be given to the Organisation’s Administrators and to its billing contact, and takes effect from the Organisation’s next renewal. Where a Team Plan is paid annually in advance, this means the renewal following the notice period, and not the period already paid for.

6. Acceptable use

You agree not to:

  • use the Service unlawfully or for any unlawful purpose;
  • copy, scrape, harvest, or systematically extract content or data from the Service;
  • reverse engineer, decompile, or attempt to derive the underlying methods, models, or source code of the Service;
  • resell, sublicense, or commercially exploit the Service without our prior written permission;
  • share login details, or allow the Service to be used by more people than the number of licences held;
  • interfere with or disrupt the Service, or attempt to gain unauthorised access to it or its systems; or
  • use the Service in any way that could damage, disable, or overburden it.

7. Intellectual property

The Service, including its calculators, methods, models, design, text, and other content, is owned by us or our licensors and is protected by intellectual property laws. We grant you a limited, non-exclusive, non-transferable, revocable licence to use the Service for your own internal and professional purposes in accordance with these Terms. No other rights are granted. You must not remove or obscure any ownership notices.

8. Limitations of use and disclaimer

  • Estimates only. The calculators and tools produce estimates and indicative results based on the inputs you provide and on published engineering methods, models, and correlations. These models are simplifications of complex, site-specific physical and chemical processes and will not capture every factor relevant to your situation.
  • Not professional advice. The outputs do not constitute engineering, regulatory, scientific, legal, or other professional advice, and are not a substitute for the judgement of a suitably qualified and experienced professional who has assessed your specific circumstances.
  • Your responsibility to verify. Before relying on or acting on any output, you must independently check the inputs and results, confirm that the method is appropriate for your water, plant, and conditions, and verify the outputs against applicable standards, regulations, and guidance — including, where relevant, the Drinking Water Standards for New Zealand, the Drinking Water Quality Assurance Rules, Taumata Arowai requirements, and applicable AS/NZS standards — together with site-specific data and your own professional judgement.
  • Safety-critical decisions. The Service must not be used as the sole basis for any decision affecting drinking-water safety, public health, regulatory compliance, or the design, operation, or control of a treatment process. Responsibility for compliance with all applicable laws, standards, and consents rests with you.
  • No warranty. While we take care in developing the Service, we do not warrant that the calculations, models, data, or content are accurate, complete, current, error-free, or fit for any particular purpose. The Service is provided on an as-is and as-available basis.

9. Consumer Guarantees Act 1993

Nothing in these Terms limits any rights you may have under the Consumer Guarantees Act 1993 or the Fair Trading Act 1986 that cannot lawfully be excluded. Where you acquire and use the Service for the purposes of a business, you agree that the Consumer Guarantees Act 1993 does not apply, and that it is fair and reasonable for you to be bound by this provision.

A Team Plan is acquired for the purposes of a business. Where an Organisation subscribes to a Team Plan, it acquires and uses the Service for business purposes and the Consumer Guarantees Act 1993 does not apply to that subscription.

10. Limitation of liability

To the maximum extent permitted by law, and subject to clause 9:

  • we are not liable for any indirect, incidental, special, or consequential loss, or for loss of profits, data, goodwill, or business; and
  • our total aggregate liability arising out of or in connection with the Service is limited to the greater of the amount you paid us for the Service in the twelve months before the event giving rise to the liability, or NZ$100.

Nothing in these Terms excludes liability that cannot be excluded by law.

11. Indemnity

You agree to indemnify us against any loss, claim, or expense arising from your misuse of the Service or your breach of these Terms. Where the subscription is a Team Plan, the Organisation indemnifies us on the same basis in respect of use of the Service under its Team Plan, including use by its Members.

12. Third-party services and links

The Service may rely on or link to third-party services (for example, payment and hosting providers). We are not responsible for third-party services or content, which are governed by their own terms.

13. Changes, suspension, and termination

Changes to these Terms. We may update these Terms from time to time. The current version will be posted with its effective date. Changes apply from the date they are posted and are not retroactive. Where a change materially affects a paid subscriber, we will give notice by email or within the Service, and the change will take effect at that subscriber’s next renewal. Continued use of the Service after a change takes effect means you accept it.

Suspension and termination for breach. We may suspend or terminate your access immediately where you breach these Terms, or where we reasonably suspect unlawful, fraudulent, or abusive use.

Free users. The free calculators are provided at our discretion and without charge. We may change, restrict, or withdraw free access, in whole or in part, at any time and without notice, and we have no liability to free users for doing so.

Discontinuing the Service. We may discontinue the Service, or any part of it, at any time. If we discontinue the Service (or discontinue Premium) while you or your Organisation holds a paid subscription, we will give reasonable notice where practicable, and we will refund the unused portion of the fee paid for the current billing period, calculated on a pro-rata basis from the date access ends. Where a Team Plan has been paid annually in advance, the refund is calculated pro-rata across the remainder of that annual period. That refund is your sole remedy in respect of the discontinuation, and no further compensation is payable. This clause does not apply where access is terminated for breach.

Your data. The calculators store your working data in your own browser, and exports you download remain yours. We do not undertake to retain, retrieve, or return any data on termination or discontinuation, so you should export anything you wish to keep. Where you subscribe to a Team Plan, we also hold the account records described in clause 14.

No guarantee of availability. We do not commit to any level of uptime or continued availability, and the Service is provided on an as-available basis as set out in clause 8.

14. Team Plans

This clause applies where a subscription covers more than one person under a single organisation account (a Team Plan). It applies in addition to the rest of these Terms. Where this clause conflicts with another clause, this clause prevails in respect of Team Plans.

In this clause: Organisation means the legal entity that subscribes to a Team Plan; Administrator means an individual authorised to manage the Organisation’s Team Plan; Member means an individual granted access to the Service under the Organisation’s Team Plan; and Seat means one licence for one named individual.

14.1 Who this agreement is with

Where a Team Plan is purchased, this agreement is between us and the Organisation, and not the individual who completes the purchase. The individual who purchases or requests a Team Plan warrants that they are authorised to enter into this agreement on the Organisation’s behalf and to bind it to these Terms. If you are not authorised to do so, you must not purchase or request a Team Plan.

Members are bound by these Terms in respect of their own use of the Service. The Organisation remains responsible for all use of the Service under its Team Plan, including use by its Members.

14.2 Seats

A Seat licenses one named individual. Seats are not concurrent licences, and must not be shared, rotated between individuals, or used by more people than the number of Seats held.

Access is linked to a Member’s email address. A Member must sign in using the exact email address the Administrator has added; access does not apply to any other address.

An Administrator occupies a Seat. An Organisation holding five Seats may therefore grant access to five people in total, including its Administrator.

Where we reasonably suspect that Seats are being shared or that more people are using the Service than the number of Seats held, we may investigate, and may suspend access or require the purchase of additional Seats.

14.3 Administrators and Members

An Administrator may add and remove Members, change the number of Seats, grant and revoke Administrator rights, update the Organisation’s billing contact, and manage the Organisation’s subscription. Actions taken by an Administrator are taken on the Organisation’s behalf and bind it. An Organisation may have more than one Administrator, and at least one Administrator must remain on the account at all times.

What Administrators can see. Administrators can see, for each Member of their Organisation, the Member’s email address, their role, the date they were added, and the date they last used the Service. Administrators cannot see the content of a Member’s calculations, inputs, results, or saved work.

Removing Members. An Administrator may remove a Member’s access at any time. Changes to access, including removals, may take up to one hour to take effect. Where a Member is removed, we retain a record that the Member previously had access so that access can be restored if the Organisation chooses. We do not retain the Member’s calculations or saved work as part of that record, and an Organisation may ask us to delete the record at any time.

14.4 Payment by invoice

Availability. Payment by invoice is available to New Zealand organisations on annual Team Plans, at our discretion. All other subscriptions are paid at the time of purchase.

Approval. A request to pay by invoice is a request only and creates no agreement until we approve it. We may decline a request at our discretion and are not required to give reasons. No charge arises from a request we decline.

Payment terms. Invoices are payable within 30 days of the invoice date unless we agree otherwise in writing. Access begins when we approve the request and is not conditional on payment having been received.

Purchase orders. Where an Organisation supplies a purchase order number, we will include it on the invoice. A purchase order is for the Organisation’s internal reference only. Any terms, conditions, or requirements printed on, attached to, or referenced by a purchase order, order form, or similar document do not apply to this agreement and do not vary these Terms, whether or not we acknowledge or act on that document. These Terms prevail. Where the Organisation’s internal procedures require a purchase order, it is the Organisation’s responsibility to provide a valid one before an invoice is raised, including on each renewal.

Late payment. If an invoice is not paid by its due date, we may suspend or cancel the Organisation’s access. We may, at our discretion, continue to provide access while an invoice remains unpaid. Any such continued access is a concession and not an entitlement, does not waive the amount owed, and may be withdrawn at any time. Amounts remain payable whether or not access is suspended or cancelled.

14.5 Renewal

Team Plans renew automatically at the end of each billing period, at the then-current price for the number of Seats then held, unless cancelled before the renewal date. Where an Organisation is invoiced, we will issue a renewal invoice on the same terms. Where the Organisation’s procedures require a new purchase order for each financial year, the Organisation must provide it before renewal, and we are not responsible for delay or non-payment arising from a purchase order the Organisation has not provided or renewed.

14.6 Changing the number of Seats

Adding Seats. Seats may be added at any time. Additional Seats are charged from the date they are added, pro-rated for the remainder of the current billing period, and are charged or invoiced at that time.

Reducing Seats. Seats may be reduced only to a number equal to or greater than the number of Members holding active access; Members must be removed before the corresponding Seats can be released. Reductions take effect at the next renewal. We do not refund Seats mid-term. Where an Organisation has paid annually in advance, a reduction is credited against the renewal invoice rather than refunded. Where an Organisation is invoiced, Seat reductions are arranged by contacting us rather than through the Service, so that any credit is applied correctly.

14.7 Cancellation and its effect on Members

An Organisation may cancel its Team Plan at any time through the customer portal or by contacting us. Cancellation takes effect at the end of the current billing period. We do not refund unused time on a period already paid for, except where these Terms or the law require otherwise.

On cancellation, or where a Team Plan lapses for non-payment, all Members lose Premium access at the end of the period, and may continue to use the free calculators. We retain the Organisation’s Member list so that access can be restored if the Organisation subscribes again, and the Organisation may ask us to delete that list at any time.

Changes to access arising from cancellation, suspension, or the removal of a Member may take up to one hour to take effect.

15. Governing law

These Terms are governed by the laws of New Zealand, and you submit to the non-exclusive jurisdiction of the New Zealand courts.

16. Contact

Questions about these Terms can be sent to support@watercalcs.com.