How low can we go?

How can we reduce our water use, to help save our chalk streams?

Many Cam Valley Forum members are concerned about the health of our Chalk streams, so monitor their water use carefully. Some are already achieving water use well below average, ranging from 50 to 80 litres per person per day.  This compares to the current average use of around 150 litres per person per day, and the design target for new homes (specified in the draft Greater Cambridge Local Plan) of 80 litres per person per day.

To explore where the savings come from, some members have shared their water usage with us.  We have compared a careful ‘Low Water Use Household’, using around 50 litres per person per day, with a ‘High Water use Household’ using around 180 litres per person per day.

We estimated how much water they were using for different purposes and compared the households, as shown in the chart below.

Both households are 2 retired people living in homes with a garden. Other households may have different water usage patterns of course, for example if they have young children, or do a lot of mucky activities, or they’re out at work a lot of the time. Nevertheless the comparison is revealing.

Although the water efficiency of appliances affects water use, and their installation should be encouraged, the choices each household makes about how it uses water are often more important.

These choices, in order of importance are:

  1. hosepipes,
  2. showers and baths,
  3. the washing machine,
  4. toilets.

We looked at why the 2 households were using such different amounts of water for each of those key activities.

The Hosepipe. This is the most important differentiator, using about 170 litres in 10 minutes. This is why, even in summer the careful Low Water Use Household will very seldom use the hosepipe, typically instead collecting rainwater and water from the washing up (they do not use a dishwasher). This is then used for cleaning or to water the garden, as shown in this short video  

In contrast the High Water Use Household typically uses a hosepipe for 10 minutes a day in summer. Even in this short period the hosepipe nearly doubles the household’s water consumption, using more in 10 minutes than the Low Water Use Household uses all day.

Showers and baths are typically the second biggest differentiator between low and high water users. A modern water efficient shower head typically uses around 7 l/min. The two person Low Water Use Household shown in the graph takes 2 short showers per day, together totalling 5 minutes.   They seldom take baths, which use a lot more water than a shower. 

In the High Water Use Household the showers are estimated to take twice as long, at a total of 10 minutes a day for the 2 people. This consumes three quarters of the water that the Low Water Use Household uses for all purposes. If the High Water Use Household had a power shower or took regular baths (which can easily use 80l per use) their water use would be even higher.

The washing machine.  A typical modern, water efficient, washing machine uses around 43 l/load. The Low Water Use Household tries only to use the washing machine “when needed” which results in typically running one load per week. 

In the High Water Use Household, clothes are washed more or less every time they’re worn, resulting in the washing machine being used daily. As the graph shows this consumes half the water that the Low Water Use Household uses for all purposes in a day.

Toilets are the 4th most important differentiator.  While each flush of a modern low flow toilet uses around 4.5 l / flush (a tenth of the water that an old fashioned one uses) households make very different choices about how often they flush.  Typically, the Low Water Use Household only flushes “when needed” adopting the principle “if its yellow, let it mellow, if its brown, flush it down” flushing around 6 times a day.  

The High Water Use Household also has a modern low flush toilet, but flushes every time, estimated at around 10 times a day.   This simple choice means they flush away nearly half the water that the Low Water Use Household uses for all purposes.  Their water use would of course be much worse if they were also using an old fashioned toilet with a big cistern, which could use as much as 30l per flush.

As this shows, although owning water efficient appliances helps us reduce consumption, our personal choices usually make a much bigger difference.  Those using less than 80 litres per person per day can probably feel that they’re doing their bit to help save the Chalk streams.

Photo: Wild Trout Trust, Hoffer’s Brook Chalk Stream

However, it’s not sufficient to rely on the good will of a minority to help save our Chalk streams. This is why Cam Valley Forum is calling for Cambridge Water to introduce hosepipe bans (a.k.a Temporary Use Bans) every summer.

A senior Environment Agency manager has told us they are “surprised and disappointed” that Cambridge Water has not already introduced these.

If you’re not sure how to track your water usage, read this short article

Cam Valley Forum calls for Cambridge Water to impose a Temporary Use Ban from 1 July

The following motion was presented to the Annual General Meeting of Cam Valley Forum, held on 20th March 2023

In the face of drought, as is still declared by the Environment Agency, and to protect the aquifer sources of our ailing Chalk streams, the Annual General Meeting of the Cam Valley Forum calls on the Cambridge Water Company to act responsibly by instigating Temporary Use Bans from 1st July 2023.

More than 50 members present discussed the reasons for, and implications of this motion and then voted overwhelmingly in favour of it. 

We set out below the reasons for doing this

The need to conserve water-

The failure of the Chalk aquifer to adequately recharge following last summer’s drought is evident from the Environment Agency hydrology reports and, despite recent heavy rain, we are still in drought measures.  We live in an area that has the least rainfall in England and yet our population is expanding more rapidly than elsewhere.  To meet demand, Cambridge Water Company (CWC) is pumping too much water out of our chalk aquifer and this causes our precious chalk springs and streams and village ponds to dry-up.  The current situation is not sustainable, and significant damage is being done to the area’s biodiversity.  We support CWC’s proposals for the new Fen Reservoir, however this will not be in place until after 2035, and so we must find ways to conserve water from now until then.

Raising awareness-

Cambridge Water’s bills include the ‘Waste not one drop’ message and the Cambridge Water website gives advice and support on how to save water, however consumers are still using around 140 litres of fresh water each day and the usage of water increased by an estimated 25% in last summer’s drought.  The most effective way to make people aware of the need to use water sparingly is to impose a Temporary Use Ban (hosepipe ban).  This is justified as a means of helping our depleted aquifer to recover and preventing environmental harm.

We and other local groups, will be broadcasting and publicising the implications of the Environmental Emergency that we are facing and calling on Cambridge Water Company (CWC) to impose the TUB.

Avoiding delays in implementing a TUB-

The UKWIR’s code of practice when considering how to implement temporary use restrictions is flawed!  This is because it takes a minimum of 5 weeks for a TUB to be implemented after the need for it has been triggered.

This delay meant that TUBs were imposed much later than they should have been, for example Yorkshire Water imposed theirs between 26th August and 6th December 2022. The more stringent Non-Essential Use Ban (NEUB) takes 3 months to implement, and so if this summer sees a very severe drought and the justification for a NEUB is triggered in August, it will not be imposed until November!  Water Authorities need to be proactive and anticipate the need for a TUB well in advance.   The justification for the CWC TUB is the need to allow the depleted aquifer to recharge. So we suggest that internal communication and governance, and external communication with the Environment Agency, regional groups, and neighbouring water companies should happen this May.  The 21 days for comments, to include at least 14 days for representations to be made, could then take place at the start of June. The drought management team could then consider representations from individuals or groups in a fair and even‐handed manner, and any decisions made could be communicated to both the individuals or groups and the public before the end of June.  This would allow the TUB to be announced through local press and media in late June ready for implementation by not later than 1st July 2023.

Cambridge Water Drought Plan is not fit for purpose-

Cambridge City Council declared a climate emergency in 2019, and the lack of water is certainly one of the most influential factors in the formulation of the emerging Greater Cambridge Local Plan.  Why in the light of this, is Cambridge Water’s published level of service is ‘to introduce a temporary use ban or TUB on water use on average not more than once in 20 years’?  Do CWC not envisage taps running dry as water is pumped out from deeper and deeper into the aquifer?  Might this suggest that CWC is not sufficiently meeting the obligations to our natural environment as defined by Water Resources East? 

The CWC Drought Plan states that it is not until Drought Trigger 2 is reached that TUBs would be considered.  At Drought Trigger 2 CWC expect to be experiencing medium severity drought without sign of immediate recovery or lessening of impact.  The impact of such drought conditions would be compounded by the damage to the aquifer sustained by abstraction during previous years’ droughts.  The procedure that requires the lapse of 5 weeks from that trigger point until a TUB can be enforced is not fit for purpose.

We have written to CWC informing them of this motion, and urging them to to work with us in justifying a TUB to be imposed by not later than 1st July 2023, to enable some recharge to our depleted aquifer. 

We received the following reply on 5 April

A National Chalk Stream Restoration Plan

Inspiring annual lecture by Charles Rangeley-Wilson at our AGM on A National Chalk Stream Restoration Plan: the next steps to save our rivers

Watch it here:

Charles Rangely-Wilson’s work and advocacy on behalf of Chalk streams is without equal. A well-known river environmentalist, author and Wild Trout enthusiast Charles Rangely-Wilson is Chairman of the National Chalk Stream Restoration Group. His writing has been described as ‘capturing the essence of time and place in ways that open your eyes to what you are missing’.

AGM 2021 and Annual Talk, 7:30pm-9pm Thursday 25 March

Cam Valley Forum AGM at 7.30 pm, followed by the annual lecture by Charles Rangeley-Wilson at 8pm on A National Chalk Stream Restoration Plan: the next steps to save our rivers

Charles Rangely-Wilson’s work and advocacy on behalf of Chalk streams is without equal. A well-known river environmentalist, author and Wild Trout enthusiast Charles Rangely-Wilson is Chairman of the National Chalk Stream Restoration Group. His writing has been described as ‘capturing the essence of time and place in ways that open your eyes to what you are missing’.

Do join us, participate in our AGM, hear from Charles Rangeley-Wilson and help us all guarantee a future for our chalk streams.

Register for this event here, and you will be sent the zoom link a few days beforehand.

Letter to minister

We are delighted that Anthony Browne MP for South Cambridge is joining us in calling on Defra to establish a ‘Chalk Streams Task Force’ to develop a Strategy to restore natural flows to Chalk streams.  We have worked with Water Resources East to draw up an eight-point plan to kick-start the Task Force’s work.  We are working to build a strong coalition of support for this initiative, which recognises that national policy on managing our water resources has to change.

You can download Mr Browne’s letter to the DEFRA Minister, Rebecca Pow, and our initial plan below

Publication of our report “Let it Flow!”

River Granta at Stapleford, Sept 2019

Cam valley Forum publishes Let it Flow! – detailed proposals to restore the River Cam

Our new report – Let it Flow! – explains the environmental impact of water abstraction on the Cam Valley and calls for actions in seven main areas to protect and restore the river:

  1. Substantial reductions in groundwater abstraction from the aquifer that feeds our Chalk streams. Where the water environment is being damaged, licences need to be amended or terminated to deliver real cuts in actual abstraction, not just paper savings in licensed amounts
  2. Investment in new sources of public supplies. Proposed strategic north-south transfers of water should be extended to benefit the Cam Valley too. Locally, high river flows should be captured in a new reservoir in the lower Cam Valley, once they have flowed through it in as natural a way as possible, and be redistributed as necessary.
  3. Investment in water reuse and aquifer recharge schemes. Sewage treatment works need to be upgraded to deliver better treated water to be reused for public supplies and to recharge the aquifer and/or to support irrigation.
  4. Investment in the harvesting of rainwater and recycling of greywater. Our local planning authorities need to ensure that schemes to harvest and recycle water become commonplace and help to make Cambridge a ‘Water Sensitive City’.
  5. A step-change in attitudes to water use through metering, leakage control and demand management. Cambridge should become the ‘No. 1’ water-saving city and the Anglian Region the ‘No. 1’ water saving region in England.
  6. Significant reductions in water pollution and investment in work to enhance habitats and natural processes. Action is also needed to: reduce pollution from land, businesses and homes; and to rectify the impacts of past river modifications, which have reduced connectivity between reaches (e.g. weirs) and between rivers and their floodplains.
  7. Improved resilience, not only for public water supplies but also for the environment. An increasing population, economic growth, intensive land management, and climate change, will all bring new pressures to bear on the Cam Valley’s limited and precious water resources. We all have a moral obligation to protect our river environments for future generations to enjoy.

Our 12 further recommendations are being submitted to Water Resources East, the body currently charged with planning the future for water resources in our Region. We want to work with the other members of Water Resources East to create an ‘Integrated Water Resource Management Plan’ to secure the best possible outcomes from this process.

We commend Let it Flow! to everyone with an interest in the environment of the Cam Valley.  We would welcome comments and support and look forward to developing our ideas further in close consultation with all relevant interests in the months to come.

You can download the full Let it Flow! report here and the four-page summary with the 12 recommendations here