Articles and spreedsheets to help you with the calculations necessary to design gravity flow water systems.
Information about water systems that require no pumps to make them work, using only the contours in the terrain to deliver clean drinking water.


Sections:
Articles:
Fluid Mechanics For Gravity – Flow Water Systems and Pumps
A text detailing the design of water systems including the design parameters recommended for a successful and long lasting water supply. Issue 2 May 2003.
Natural Flow Calculator Spreadsheet
This spreadsheet allows the user to calculate the natural flow rate (LPS) of any combination of up to 4 pipes of different diameters (in) for given pipe lengths (m) and known head (m). Microsoft Excel Spreadsheet (165KB) *** Note: this spreadsheet contains macros, and you may get a security warning.
Head Loss Calculator Spreadsheet
This spreadsheet allows the user to calculate the frictional head loss (m) for a given flow rate (LPS) and pipe length (m), for a series of different diameter pipes (in). The user can also find the optimum combination of 100m sections of two pipes of different diameters (in) to “burn off” a given frictional head […]
Friction Loss Tables
Data for frictional losses in plastic pipe Diameter: 1375mm, Flow rates: 0.063.15LPS, Frictional coefficient: C=150 This table is available as a PDF.

Gravity Flow Design & Construction
Documents that cover everything you will need to know about the design, construction and operation of gravity flow water systems.
Articles:
Gravity Flow Water Supply
By Santiago Arnalich Castañeda. This book intends to provide you with the tools needed to complete a sucessful gravity flow water project in a short amount of time. You may well already be dealing with a real life project, but without the time to do intensive study to get up to scratch. This book is […]
Construction of a Gravityfed Water Supply and Treatment System in Developing Countries
This paper covers every aspect of the design and construction of a water supply system utilizing potential energy (gravity) for delivery. The typical layout of a gravityfed water system includes a water source, transmission main, reservoir and distribution system. Every component between the water source and the reservoir is discussed in this paper, which focuses […]
Small Community Water Supplies
This book is a very good place to start learning about building a water supply. It covers all the things that you will need to know about sourcing water including rain water harvesting, spring, wells and surface water. It also has sections on water quality and treatment. This book is made available here as PDF […]
Water System Design Parameters
Condensed from A Handbook of GravityFlow Water Systems, Thomas D. Jordan Jnr., Intermediate Technology Publishing. It can be downloaded as a PDF. The following are a list of design parameters that are important in the design of gravityflow water systems: Maximum Pressure Limits : The taps and valves closed state, should be the maximum pressure […]
The Anatomy Of A Gravity Flow Water System
This section contains photographs that detail the construction of a gravity flow water system for 32 families. The system cost £130 per family and took 30 people 18 days to build. Before the system can be designed the area must be surveyed. The system consists of: A spring tank; A main pipeline, including a pipe […]
Understanding GravityFlow Pipelines: Water Flow, Air Locks and Siphons
Useful factsheet from the British Colombia Ministry of Agriculture and Lands detailing the problems and solutions of gravity flow pipe system design. Calculating water flow, pipe size, understanding air locks, and using siphons are covered. Examples and references are given. Uses imperial units. This document is available a PDF.
Fluid Mechanics For Gravity – Flow Water Systems and Pumps
A text detailing the design of water systems including the design parameters recommended for a successful and long lasting water supply. Issue 2 May 2003.
