Our purpose
Irrigation Calculators exists to help homeowners, landscapers and growers make better watering decisions with clear tools built on established engineering and agronomy. Every page should answer a real question accurately, show how the answer was reached, and be honest about what it can't tell you.
Who is responsible for our content
All calculators, reference charts and guides are published under the responsibility of Daniel Reeves, PE, CID, a licensed Professional Engineer and Irrigation Association Certified Irrigation Designer with more than 20 years in irrigation design, system auditing and landscape water management. He reviews the methods, formulas and sourced values on every page before it's published.
Each page names its author, shows when it was last updated and reviewed, and lists the checks carried out for that page.
Editorial standards
- Accurate. Every number on a page is calculated, taken from a named source, or clearly labeled as a typical value.
- Transparent. Calculator pages show their formulas, worked examples, assumptions and sources.
- Clear. We write in plain English, explain technical terms the first time we use them, and put the answer before the explanation.
- Balanced. Where methods or sources differ, we say so and explain the difference rather than presenting one view as the only one.
- Nothing invented. We don't publish made-up statistics, studies, quotes, testimonials, ratings or credentials.
- Written for readers. We write to answer the reader's question, not to fill a page. Every section has to help someone use the tool or understand the result.
- Accessible. Our pages work on phones, tablets and desktops, with a keyboard and with screen readers.
Sourcing and citations
We rely on standards bodies, government agencies, university extension services and peer-reviewed research, and on manufacturers' published data only for equipment-specific values. Sources are listed on every page that uses them, and when a claim depends on a specific source, we name it in the text.
A number attributed to a source is a number that appears in that source. When sources disagree, or a source contains an evident error, we point it out on the page. Our methodology describes the formulas, constants, rounding rules and checks behind every calculator in detail.
Review before publishing
Before a page goes live, it's checked for:
- formulas that match their sources and the calculator's code;
- worked examples that match the calculator's output exactly;
- sourced numbers that match the sources they're attributed to;
- clear error messages and no invalid results for any input;
- correct behavior in US and metric units;
- usability on different screen sizes and with a keyboard.
A page that fails any of these checks isn't published until it's fixed.
Independence
We don't sell irrigation products or design services, and our author doesn't either. Our calculators and recommendations aren't shaped by any manufacturer, retailer or advertiser.
- Manufacturer data is data, not endorsement. When we name a manufacturer, it's because we're citing its published specifications for a specific product type.
- No paid placement. We don't accept payment to include, rank or recommend products, companies or links.
- Advertising is kept separate. If the site shows advertising, it's clearly separate from our content and has no influence on calculations, results or recommendations.
Safety and local rules
Our results are planning estimates, not a site-specific design. We say so on every page, and we remind readers that local watering restrictions, backflow requirements and landscape ordinances come first.
Pages involving fertilizers or chemicals always include safety cautions: follow the product label, use required backflow prevention and protective equipment, and follow local regulations. The label and local rules take priority over any calculated amount.
Updates and dates
Every page shows an "Updated" date and a "Last reviewed" date. We review a page when one of its sources is updated, when we find a better source, when a reader reports a problem, or when we improve the calculator. We change the dates only when the page has actually been updated or reviewed.
Corrections
If you think a result, formula, value or source on our site is wrong, please contact us. Tell us which page it's on and, for a calculator, the values you entered. We check every report against the original sources. If we find an error, we correct it promptly and update the page's review date.
Contact
Questions about this policy, suggestions for new calculators and error reports are all welcome through our contact page. You can learn more about the site and read our privacy policy and terms of service.