The SuDS maintenance challenge

26 February 2026

Retrofitting SuDS at scale has huge potential for reducing runoff to sewers, but this technology only works if it’s properly maintained

Sustainable drainage systems (SuDS) are a disruptive technology. SuDS are modifications to a development or existing urban landscape that allow it to manage rainfall in ways that offer multiple benefits. They’re a means of treating urban pollution, creating better places for people and wildlife, reducing overflows from combined sewers, and improving climate resilience – including helping to reduce flooding.

Disruptive technologies are powerful forces for change but they bring with them challenges that can serve to inhibit progress. One of those challenges is maintenance. This is particularly relevant in relation to retrofit SuDS, but also to new development. Delivering and maintaining amenity value – general benefits to users of the area such as health and wellbeing, play, visual amenity, urban cooling and nature contact – should be top of our agenda when installing SuDS, no matter your delivery priorities.

The fact that we don’t have the skills and money to maintain nature-based SuDS is only relatively recently being recognised as a significant barrier to the kind of SuDS roll out that we all want to see in the UK. Ask any landscape architect and they will tell you two things: firstly, that this problem is not unique to SuDS – it’s a general and deeply frustrating problem afflicting most public green infrastructure initiatives. Secondly, it’s an issue that has been growing for decades and is still getting worse – council budgets are not going up and maintenance skill levels appear to be continuing to decline.

Throw in the ambitious scale of additional SuDS landscapes in planning for the public realm in the coming decade, on top of the existing maintenance issues, and we have a big problem we need to solve. We can’t hide behind a mythical notion of near-to-zero maintenance rain gardens.

Unrealistic expectations

Here at Robert Bray Associates, we recently had a tender invitation that included an ambition for the rain garden design to be ‘self-maintaining’. Here we see an unwitting illustration of the pitfalls of applying conventional drainage thinking to blue-green infrastructure: the ‘self-cleansing velocity’ of pipe design meets landscape maintenance. The client presumably knew that ‘zero maintenance’ wouldn’t fly, and opted for ‘self-maintaining’ as a more palatable term.

Maintenance of SuDS landscapes is not just about delivery of aesthetics and the soft benefits of SuDS – as the amenity and biodiversity benefits of SuDS are too commonly regarded. It is a critical part of ensuring continued hydraulic functionality. One of the characteristics that makes SuDS a disruptive technology, contrasting with much conventional drainage maintenance, is that ongoing, proactive, scheduled maintenance is required to maintain any or all of the ‘four pillars of SuDS’ functionality (amenity, biodiversity, water quality and water quantity according to the Construction Industry Research and Information Association).

Example of a badly-maintained sustainable drainage system (SuDS) © Kevin Barton

Added to that, the manner, equipment and skills of maintenance are radically different from those required for conventional drainage. Maintenance of vegetation in urban landscapes normally sits within the remits of parks, greenspace and public realm departments rather than with highways and drainage, or with water companies who may now feel that SuDS installations are their responsibility. This ambiguity only amplifies the disruptive impact of SuDS on the industry. Whose runoff and silt is it? Who pays whom to carry out maintenance? And do different council departments pay for and carry out different aspects of maintenance?

Nature-based SuDS cannot be fit-and-forget, zero maintenance. We should also be wary of aiming for as close to zero as we can get. Again, most landscape architects will accept that, on the whole, the potential community and wildlife benefits of a landscape reduce as we design for decreased maintenance budget. Whilst the industry is exploring new approaches to plant species, substrates and mulches to deliver more with less, there’s only so low a bar can go when we’re talking about living organisms, before what we’re delivering becomes devalued to breaking point or risks losing its community and wildlife value soon after completion.

It would be better to deliver fewer SuDS and retain – and ring-fence – the budgets to maintain them properly, even if this means challenging and re-writing the ‘rules’ around capital investment and maintenance funds. Disruptive technologies call for new rules. If the infrastructure we install is kept functional and multi-beneficial, this could result in better overall performance outcomes on multiple fronts in the long-term. Better that than building more SuDS and them failing due to neglect.

Can community maintenance save the day?

No (and yes). I’m not an advocate for free community maintenance. It’s wonderful to have local community members wanting to maintain SuDS for free – and we have schemes in Wood Green, North London, where this is the case – but we have to be very careful when adopting this as a strategy.

Some questions to consider: does the community have the necessary skills and equipment to maintain the SuDS, including the more technical bits like checking inlets, outlets and flow controls? Do they have the training, competence and equipment to safely maintain green infrastructure adjacent to highways if this is the case? How will it be guaranteed or contracted that they will maintain the SuDS to an acceptable standard, and how will this be supervised? What happens if the community impetus fizzles out and they stop maintaining the SuDS? Will this be identified before weed infestation? In case of performance failure, how will the maintenance be taken back into council (or another body’s) control?

But perhaps the biggest issue with free community maintenance is that it relies on good will, which is typically a finite resource. Fine for the odd pilot but we should be well beyond pilots by now and we urgently need to be thinking about rolling out this infrastructure on community, town and city-scale. As we scale up SuDS retrofitting, that holy grail of free community maintenance will feel like a distant dream.

The other issue of relying on community maintenance is that we risk concentrating SuDS and the benefits they bring – to health, wellbeing, quality of life, climate resilience, property values and more – in the typically more affluent communities and demographics with the capacity to maintain them for free. This could mean that more vulnerable communities miss out on the much-needed co-benefits of SuDS.

It’s just not a viable solution at scale – and nor should it be. People don’t maintain gullies and pipe networks, have to cart all their refuse to recycling centres themselves, or maintain the roads outside their houses. Why should we expect them to maintain this new, better form of drainage infrastructure, just because it brings them co-benefits?

Contracted community maintenance

I advocate community maintenance of SuDS being valued as an essential service and therefore rewarded, specified, contracted and performance monitored appropriately.

At Bridget Joyce Square, our award-winning, community-focused SuDS project in White City, London, the highly-valued urban park is maintained by a local community charity, Hammersmith Community Gardens Association (HCGA). They are under contract to the London Borough of Hammersmith and Fulham and are paid for their service. They run a smallholding locally and so the staff know how to maintain landscapes, and they are an active part of the community, dedicated to maintaining the community value that the park delivers. They use local volunteers as well as corporate volunteers to carry out the maintenance, under skilled supervision, and because they walk through it on the way to work, they are proactive in their maintenance programming.

The charity wins because it brings in much needed revenue, which supports their amazing charity work with the local community. The community wins because they have a valuable landscape that is properly maintained by members of their own. The council wins because they get reliable, effective and cost-effective maintenance and a landscape investment that is valued and protected by the local community. In fact the model has been so successful that the council has contracted them to plant and maintain a tranche of new rain gardens we designed for the estate, as well as a few other landscape projects in the area.

A bit of digging around will identify similar horticulture-based grassroots organisations and charities that could be approached to deliver similar services, bringing them revenue and public profile benefits. Where they don’t exist, we need to accept that SuDS installations ‘aren’t just for Christmas’ – we must invest in nurturing their long-term success as much as we do in their initial construction.

The most important ‘pillar’ of SuDS?

Whilst I strongly advocate for delivering the appropriate balance of the four pillars of SuDS that befits the context, I believe there is one pillar that outstrips the others in importance. Designing for amenity value – and paying to maintain that value – should be the paramount focus of any SuDS project in the public realm, no matter what your primary objectives are. This is because it’s the aspect of SuDS that can either unlock or inhibit successful delivery and maintenance of SuDS depending on how it is approached.

Even if we were only targeting hydraulic performance – reducing the rate and volume of flows discharging from the system – if the SuDS do not deliver meaningful benefits to the host community, then issues can arise that jeopardise our wider hydraulic objectives such as reducing CSOs or flooding.

The first is public rejection of or indifference to SuDS installations, resulting in a lack of care, vandalism, damage, lack of reporting of maintenance issues and lack of community pressure on councils to look after them properly. All this is important because it can potentially result in performance loss or failure. If an unappealing SuDS installation is a blot on the landscape from the start and is essentially useless to the local community, are people going to care or even notice when it’s silting up, damaged, failing or receiving foul sewage from misconnections? Are they going to park on highway rain gardens because they didn’t deliver perceivable public value and didn’t properly consider public needs and behaviour?

SuDS installations with low public value that result in negative public perception make it difficult to engage local communities and get their approval for more SuDS. This risks impacting the rate or ultimate scale of roll out. I’ve experienced this negative public feeling directly because of poorly designed or maintained SuDS, and believe we may already be in the early stages of a viscous cycle of descending public perception in the UK.

If the communities we are engaging with have only experienced SuDS with low amenity value, or poorly maintained SuDS, or have only heard of them through negative press coverage of schemes, then convincing them of the potential of putting SuDS in their community gets much harder. If we struggle to convince the broader public beyond a few pilot projects, then we may struggle to achieve the scale of retrofit SuDS that we need.

For community maintenance structures to be viable, SuDS need to bring real, meaningful value to those communities. Charities and community groups are far more likely to be willing to maintain projects that have a genuine design emphasis on meeting community needs and benefitting the local community. Such projects can generate a virtuous cycle of positive public perception of SuDS, leading to public buy in and a smoother roll out of subsequent projects.

Hydraulic functionality should be a given, not a driver of design. Instead of being seen as a soft benefit or a nice to have, the broad range of human benefits that are so inadequately summarised as ‘amenity’ in the SuDS world should be at the forefront of SuDS design. Such an approach should enable us to implement projects that communities actually value. Only by doing so will we achieve the roll out of SuDS at the pace and scale we urgently need, and secure their continued functionality into the future.

--

This article originally ran in the Spring 2025 print issue of The Environment. Become a member of CIWEM today to gain access to the quarterly magazine, as well as digital access going back to 2016. Non-members can also access the monthly The Environment digital newsletter.

You can also read about CIWEM's 'third way' approach for implementation of SuDS.

Kevin Barton is a landscape architect and managing director at Robert Bray Associates