Water Efficiency Guide

Water efficiency: a step by step guide

Reducing water use saves money, can enhance the reputation of a business and preserves natural resources. But where should a business start? This guide will help your business through the first stages of setting up a water efficiency strategy.

Water as a Resource

Water is often taken for granted: You turn on a tap, and as if by magic, it is there. However, water is a resource like any other, and hence its supply should be treated with respect.

As such, all businesses should make sure that their operations are as water efficient as possible.

The benefits are clear:

• Save money
• Save carbon emissions
• Protect the wider environment
• Avoid potentially damaging leaks

This document provides a first step for businesses wishing to use water wisely, and achieve water efficiency in their organisation. It is supplemented by the following further Water Efficiency Guidance documents in the our Information Pack:

• Billing
• The Open Water Market
• Behaviour Change
• Site Walkthrough Checklist

The Water Management Hierarchy

The Water Management Hierarchy is a framework for prioritising water management and efficiency actions.

Keep the waste hierarchy in mind when undertaking water savings actions: those which deliver results closer to the top of the hierarchy should be preferred.

The Water Management Hierarchy: What should you consider?

Reduce costs and eliminate water waste to enjoy greater savings for your business

Step 1: Understand your water use

Step 2: Set Key Performance Indicators

Measuring water efficiency performance over different time periods helps to gain a better understanding of how your business uses water and where efficiencies can be made. This is best done through setting water management key performance indicators (KPls), which are water use targets proportional to an applicable variable site activity indicator (such as production levels).

KPls allow a business to:

• Establish baseline water efficiency performance
• Track changes in efficiency over time
• Compare your water use to published  benchmarks for your industry

Typical KPl’s for water management include the following:

• Water Use: m3 per employee / site occupant or tonne of product/m3
• Effluent Strength: kg Chemical (or Biochemical)
• Oxygen Demand per tonne  of product

A key part of using KPls as effectively as possible is to analyse them graphically, in order to visualise if they remain steady, increase or decrease over time. Also, high variation in a KPI graph can illustrate poor control over water use levels. An example of such a graphical analysis is below.

Step 3: Water efficiency action plan

Once the water balance has been constructed and a baseline water efficiency established by setting KPl’s, the goal is of course to improve performance.

There are many water saving techniques, so prioritisation is key, according to factors such as:

• The budget available for investment
• The water savings possible through each action
• Operational costs of any technology solutions
• Prioritising hot water savings (heating one m3 of water to 75°C can cost over £7)

A general list of potential water efficiency technologies is presented over the page. Some of these (particularly urinals, taps, and toilets) will be universally applicable.

However, others (particularly those regarding process water use) will be site specific. In order to tap into these (which depending on the site in question can deliver the most savings), advice can be sought from:

• A water retailer such as Castle Water
• Environmental consultants
• Technology suppliers

Leakage is a key area which should be addressed (if identified by a water balance model) in any effective Water Efficiency Action Plan. The water and costs savings possible through remediating even simple leaks are shown below:

Step 4: Consider alternative water sources

Alternative water sources represent a different option to mains water. They are typically used for applications for which water treated to a high quality is not needed, including flushing toilets and urinals, grounds irrigation, and various process uses.

Alternative water sources include:

• Rain and stormwater
  Water runoff from roofs or ground areas collected and stored for reuse
• Boreholes
  Wells drilled to allow access to underground water sources
• Surface water
  Water sourced from rivers,  streams, etc.
• Reclaimed water
  Water which has already been used in onsite processes, and is reclaimed for reuse

There are multiple potential benefits of using alternative water sources. These include saving money (through reduced mains water bills) and a reduced environmental impact (by using water which is only treated to the necessary quality, and hence results in lower treatment based carbon emissions). However, they must be properly managed to ensure their safe use.

With this in mind, two British Standards are available for reference regarding the implementation and operation of different alternative water sources. These are:

• 858515:2009 for rainwater harvesting systems
• 858525-1:2010 for greywater systems

Step 5: Drive continual improvement

Steps 1 to 4 of this guide provide the basics for a SME who wishes to improve their water efficiency - and save money and improve environmental performance in the process.

However, water efficiency should be seen as a continual process, in which improvements are monitored and continuous improvement driven.