# Water Demand Calculator — Calculate Peak Water Demand

> Calculates peak water demand for plumbing systems, considering water-efficient fixtures. (iPhone/iPad app by International Association of Plumbing and Mechanical Officials.)

- Source: https://appshunter.io/ios/app/water-demand-calculator/id1463745348 (this page in markdown: same URL + `.md`)
- Developer: [International Association of Plumbing and Mechanical Officials](https://appshunter.io/developer/1455422752)
- Category: Education, Utilities
- Price: Free
- Rating: 1.40/5 from 5 App Store ratings · 4 written reviews indexed
- Age rating: 4+
- Requires: iOS 13.0 · 92 MB
- Languages: English
- Released: 2021-03-18
- Data updated: 2026-06-01
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/water-demand-calculator/id1463745348/reviews.md

## What is Water Demand Calculator?

The WDC results in more accurately sized systems consistent with the lower flow rates and consumption values from water-efficient plumbing fixtures and appliances. The WDC is designed to predict peak flow rates that would impose a demand load on any portion of the indoor water supply system including the building supply, main branches and risers, and fixture supply branches. Special Features include:

·         Preset list of Plumbing Fixtures
·         Drop down menus to add the number of fixtures
·         Can adjust flow rates lower than the preset values
·         Other fixtures not listed can be added
·         Three units of measure can be selected – GPM, LPM, and LPS
·         Calculates the peak water demand
·         Save feature allows sending results to an email, or download to your device
·         History page allows you to return to projects saved

## Key features

- Accurate system sizing
- Accounts for water-efficient fixtures
- Customizable flow rates
- Add unlisted fixtures
- Multiple units of measure
- Save and email results
- Project history

## Recent user reviews (4 of 4)

All indexed reviews: https://appshunter.io/ios/app/water-demand-calculator/id1463745348/reviews.md

### 1/5 — Does not work

*2025-12-08, version 1.0*

Nothing populates in the text box

### 1/5 — Doesn’t work

*2024-11-18, version 1.0*

Can’t enter values. I follow the instructions but nothing shows up when I try to enter data. The cursor moves but nothing shows. It appears that it just simply doesn’t work.

### 3/5 — App not compatible with night shift/dark theme

*2022-06-27, version 1.0*

Cannot read test when dark theme is enabled and/or night shift kicks in. I was able to read text in entry boxes in the daytime.  After 8 pm when the night shift kicked in, could not read text.

### 1/5 — It simply does not work.

*2021-10-02, version 1.0*

Text entered in the form does not appear.  Calculation summary is not shown.  This app is unusable.  I guess it back to excel.

## Frequently asked questions about Water Demand Calculator

### What is the Water Demand Calculator used for?

The Water Demand Calculator is used to accurately predict peak flow rates for indoor water supply systems. It helps in sizing building supply, main branches, risers, and fixture supply branches considering water-efficient fixtures and appliances.

### Can I add custom plumbing fixtures to the Water Demand Calculator?

Yes, the Water Demand Calculator allows you to add fixtures that are not pre-listed in the application. You can also adjust flow rates lower than the preset values for greater accuracy.

### What units of measure does the Water Demand Calculator support?

The Water Demand Calculator supports three units of measure for calculations: Gallons Per Minute (GPM), Liters Per Minute (LPM), and Liters Per Second (LPS).

### How can I save and access my calculations with the Water Demand Calculator?

The Water Demand Calculator features a save function that allows you to email your results or download them to your device. A history page is also available to return to previously saved projects.

### What is the age rating for the Water Demand Calculator?

The Water Demand Calculator has an age rating of 4+, making it suitable for a wide range of users.

### On which devices can I use the Water Demand Calculator?

The Water Demand Calculator is available for iPhone, iPad, and iPod devices, offering flexibility for users across the Apple ecosystem.

### How often is the Water Demand Calculator updated?

The Water Demand Calculator was last updated on March 18, 2021, with version 1.0. Further updates will depend on developer plans.

### Does the Water Demand Calculator have ads?

No, the Water Demand Calculator does not contain advertisements. It is a free application without any ad interruptions.

## Version history (last 1 release)

### 1.0 — 2021-03-18

No release notes.

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## More apps by International Association of Plumbing and Mechanical Officials

- [IAPMO Codes](https://appshunter.io/ios/app/iapmo-codes/id1457481184)
- [2026 ARCSA Technical Symposium](https://appshunter.io/ios/app/2026-arcsa-technical-symposium/id6461601001)

All apps by International Association of Plumbing and Mechanical Officials: https://appshunter.io/developer/1455422752

## Related topics

[iapmo](https://appshunter.io/ios/topics/iapmo) · [wdc](https://appshunter.io/ios/topics/wdc)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*