Feature: Water neutrality – a positive future is in the pipeline

Rickesh Miyangar, Director at consulting engineering firm Ramboll, explains what water neutrality is and how it can be achieved for Environment Journal.

With temperatures passing 40°C in the UK this year, and South-East England reportedly experiencing the longest period with little or no rain since the 1970s, summers in the UK are becoming unmistakably hotter and drier. Hosepipe bans are going to become the norm in the warmer months – and in light of this, with our water resources becoming increasingly scarce, various policymakers have raised the idea of ‘water neutrality’ as a means to tackle this issue.  

Water neutrality is the idea of water usage in the area of a new development being equal to or less than the previous total water usage. Natural England, one of the key policymakers leading the charge in this field, proposes its own working definition of the term: a development which does not increase the rate of water abstraction for drinking water supplies above existing levels.   

The concept of water neutrality is an ambitious one, and it raises several key points of consideration for developers – namely, which measures are required to ensure a site is truly water efficient, and how water neutrality can be evaluated on projects of different scales. As our summers heat up, these assessments will have more influence than ever, particularly in areas where predicted growth will render the current rates of abstraction no longer sustainable. Developers should also be aware of how the use of water in a site can affect wildlife, especially if the water being extracted is potable water. Additionally, when potable water is supplied to an area by the local trunk mains, it is important to consider the consequences of connecting larger developments to the existing infrastructure. This is to make sure that those who are already using the network are not negatively impacted.  

How can water neutrality be achieved? 

There are a number of techniques that can help a development improve its water efficiency. Installing measures such as smart meters, low-flush toilets, flow restrictors, and trigger-style hose guns can help to reduce water usage in a site, which is important for developers who will need to demonstrate that their developments are as water efficient as possible.  

However, these measures are not enough by themselves to achieve the substantial reductions dictated by the ambition of water neutrality. In addition to these techniques, developers may also need to consider making use of ‘reclaimed water technologies’ in a bid to further reduce consumption. Examples of such reclaimed water systems include the collecting of rainwater for practical uses such as flushing toilets and irrigation, or reclaiming greywater left behind in washbasins, showers and baths to be filtered and treated before then passing into a clear water storage tank.  

However, the cost of equipment for reclaimed water systems bears consideration from developers. The equipment required for these systems can increase a development’s capital expenditure, and are a financial burden to operate and maintain. Nonetheless, reclaimed water systems, either on a community or standalone scale, will offer the greatest water saving benefits, reducing stress on aquifers from over-abstraction, and reducing mains water costs. 

 Water efficiency measures are not yet mandatory, but developers should still be careful about water use during construction and think about the development’s water demands when in operation. Developers should thus consider all the options carefully when it comes to choosing the most effective measures for their site.  

Is water neutrality an achievable goal? 

There is no easy fix to the problem of water scarcity. Many obstacles must be overcome if we are to reduce water use and improve efficiency.  

While stricter regulations could encourage developers to consider water neutrality more, the fact is that restrictive requirements and ambitious targets are not always achievable due to the cost and suitability of the technologies and systems for the development in question. For example, the current Part G Building Regulations set a mandatory daily consumption of 125 litres per capita for new builds, which is relatively easy to achieve; however, a reduction to 62 litres per capita or even 80 litres per capita is much more difficult and would require extremely strict measures to be put in place.  

It may seem like achieving complete water neutrality in some developments is a long way off, but we are still in the early stages of this concept. There are still measures available to us currently that can help both sites and individuals become more water efficient and use less water, and thus have a positive impact. 

What are the longer-term implications of water neutrality? 

It seems like water scarcity is rarely out of the news at the moment, with pictures of extremely low water levels in our reservoirs making for a concerning image. This summer, many water authorities in the South of England have already imposed a hosepipe ban, with a wider-reaching national ban still on the table.   

The issues of water consumption and water neutrality will only become more pressing in the next few years. However, increased attention from lawmakers will only be a good thing; following the lead set by climate change and the pursuit of net-zero carbon, it’s only a matter of time before what is good practice becomes set in law.  

However, professionals should not be advising developers to aim for ‘net-zero’ water consumption. Instead, the first step should be to establish the predicted increase in water demand for new urban or rural developments, and then to reduce existing demand elsewhere inside the region – for example, by retrofitting existing properties to become more water efficient (known as ‘offsetting’ under current guidance). 

Water neutrality is a key goal that developers should strive for in the quest for better sustainability. Steps should be taken now to reduce water consumption, and a good understanding of existing water-saving technologies and methods in line with the latest industry research must be fostered. The goal of water neutrality is certainly an ambitious one, but with a unified and immediate response from developers in the face of increasing droughts, it is one we could achieve in the not too distant future.

Photos provided by Rickesh Miyangar and Luis Quintero