Hello, I'm Liv Garfield, Chief Executive of Severn Trent, and I'm joined today by Helen Miles, our CFO, and by Shane Anderson, our Director of Strategy and Regulation. Now, it might have taken a little longer than expected, but the draft determination is finally here, and today, we're gonna give you our initial thoughts on the hundreds of pages, the thousands of models that were released by Ofwat just under two weeks ago. Now, of course, the first thing that everyone wanted to know was the categorization of the plans, and we're absolutely delighted that Ofwat have recognized the quality and the ambition of our plan by giving us outstanding status. Now, that gives us both financial upside, but also some extra certainty on some critical issues, which we'll touch on later. The second bit of exciting news for our investors is that we've now locked in record RCV growth.
Now, we've been talking about that for a while, but it's actually confirmed in the draft, and it's come out actually at 28% real, which is a massive increase from the 10% we've achieved as real in AMP7, and even that considers with our sector-leading green recovery program. Now, it's a function of the biggest investment program in our history, and we're really pleased that a significant chunk of our TOTEX has now also already been approved. Our base costs have been proven to be efficient by Ofwat and are therefore in line with the submitted plan, and we get a little bit more protection, actually, some extra protection on some costs, which we'll come onto later. Now, the need for investment is what underpins all 13 of our enhancement cases, having been firmly established and approved as the need by Ofwat.
Of course, that doesn't mean we agree with Ofwat on every last pound of spend, but we're confident we've got some really good evidence to push that investment up even further as we get to the final determination. And that's our job between now and Christmas, because whilst we know there's a lot more about our future is clear now, the draft determination, remember, is just partway through the overall price review process. And we think this is a great starting point for our engagement with Ofwat before we get to that all-important final determination on the 19th December. Now, whilst we're working with Ofwat to get the best plan for all of our stakeholders, rest assured, everyone else in the business is getting on with closing out AMP7 successfully and accelerating AMP8 investment spend as well.
So let's have a little look at some of the detail in a bit more of a close-up look. Now, of course, I want to start with our outstanding status. Now, we thought for a while, to be fair, that we'd put in a really good plan. We thought it ticked the key tests of affordability, deliverability, financeability. But nonetheless, we're not gonna argue it was lovely for that to be recognized by our regulator, too. And I just wanna say thank you. It's a real testament to the hard work of the many thousands of employees, and in particular, all the teams that wrote the price review document all across the business. And it's not just a nice to have, actually, outstanding status, it does bring with it some pretty real, tangible benefits. So first and foremost, we've received GBP 93 million worth of additional financial reward.
We also know, secondly, that our WACC and our base costs can only improve from this point on, and we lock in a 50/50 cost-sharing rate, which is not true for everyone in the sector. Now, to make sure our outstanding plan is truly deserving, Ofwat did ask for us to also commit to three things to secure those benefits that I've just listed. And all of these, I'm beyond confident we can deliver. They've asked us to deliver EPA 4-star at least once in AMP8. Now, don't forget, we've achieved 4-star status every year so far this AMP, and it continues to be the number one priority for us as an organization each and every year. Secondly, they've asked us to reduce spills. Now, we are completely mission-focused on that right now in the organization.
We've got boots on the ground across the piece, delivering improvements at 900 sites this year alone. The third thing Ofwat asked for was for us to increase our affordability package by a total across the AMP of GBP 25 million. Now, that means it now represents a fantastic GBP 575 million worth of support for our most vulnerable customers. Given the level of RCV growth that we're delivering, it feels that having the right affordability support in place is something that we see as actually genuinely important, and that's why in our submitted plan, we'd already committed to eradicating water poverty by 2030. So we're absolutely delighted to be able to contribute that as well. So as a reminder then, what is in this outstanding plan, and why should all of our stakeholders be really excited about it?
Now, there's absolutely loads that I could cover off. I could literally spend hours, but I'm just gonna quickly touch on some of the big highlights. So customers are gonna get a brilliant step change in service, whether it's leakage or water quality or customer service. That's against a backdrop they're gonna be paying the second lowest bill in England and Wales, with extra affordability support, as I mentioned earlier. For the environment, we're literally gonna transform the rivers in our region, including a GBP 1.2 billion investment, reducing some of river spills. We're also gonna build in loads of resilience to meet our future water needs, make sure we don't ever have water scarcity, and we've also got enough support to really push ahead to get to Net Zero by 2030.
Finally, for our investors, well, you're part of a business with 28% real RCV growth, but also, critically, even greater certainty of growth out to 2050 and beyond, which I want to spend a little bit of time on right now. Now, you might remember we actually asked for 31% real growth, and so far, we're at 28% real growth. So not a dramatic shift in the headline numbers, actually, and considerably higher than what we've seen historically, which you can see on the slide next to me. That growth is despite not getting every single pound we've asked for, a chunk of which we're confident we've got really great evidence for, and you can rest assured we're gonna be discussing all of those points with Ofwat over the coming weeks.
So based on the numbers in our DD, our RCV would generate a GBP 2.5 billion return in AMP8 alone. But of course, this is not a single AMP situation. The benefits, actually, of the decisions that we've now received will continue long into the future. Every single one of our enhancement cases has been approved to some extent in our draft determination, and that means that the need for investment has been firmly established. Now, whether that's climate change, population growth, environmental improvements, and that means in the longer term, it unlocks huge amounts of investment between now and 2050. So look, to bring it to life, let me give you a couple of examples. So we've just had GBP 1.2 billion of investment on storm overflows approved in AMP8. That's stage one of a GBP 4.4 billion program of work.
We've just had under GBP 1 billion of water resources spend approved in AMP8, and that's the first chunk of a GBP 3 billion of investment that we can see between now and 2050. Now, all of that future investment means that we're entering into a period of multi-AMP investment and significant multi-AMP RCV growth. Now, I think that's exciting for us as an organization to imagine investing that money for the good of our customers. It's exciting, I believe, for our investors to have a real sense of the growth opportunity for this business. But also, it is genuinely exciting for our customers to know they can expect to see these real, tangible benefits coming forward in the years to come. But let's bring you right back now to AMP8.
I'm gonna hand over to Helen and then to Shane to take us through further some of the finer details of that draft determination. Helen?
Thanks, Liv. We're delighted the draft determination confirms AMP8 will be our largest investment program so far, with GBP 4.3 billion more TOTEX than we were given in AMP7. While our enhancement spend is GBP 1.4 billion lower than we submitted in our plan, we will be engaging with Ofwat over the coming weeks to provide evidence to justify the additional investments we want to make. We see real opportunity to increase that investment program even further. Ofwat have included in their documents the chart you can see in the bottom left, demonstrating typical changes between now and the final determination. Base costs look GBP 700 million lower as a result of two new mechanisms that they've introduced, which tackle two of the biggest areas of uncertainty in our operating costs.
First, on energy, which has been incredibly volatile for all businesses in recent times, there will be a true-up of the difference between forecast prices and our actual prices. And secondly, on business rates, which have been increasing for a number of years, there'll be an enhanced customer sharing ratio, which means we are significantly less exposed to rate increases. On enhancement spend, Ofwat have again built in some protection against higher-than-inflation cost increases. First, where the cost of materials, plant, and equipment is above inflation, we will be reimbursed for the difference. And secondly, a sharing ratio of 40% will be applied to all enhancement spend, meaning the company's share of any overspend is 40%, rather than the current 50%. This protection reduces the risk around some of our most sensitive costs and importantly, protects economic value.
But of course, the timing impact on cash flows will also need to be considered as we review the plan. So if we take a look at base and enhancement costs, starting with base costs, which are essentially our running costs and critical to running the business effectively every day and to drive operational performance. We're really pleased that after adjusting for around GBP 700 million of energy and rates, our base costs are in line with our submitted plan, and that's a reflection of our strong track record on efficiency, which is confirmed by Ofwat's models, which showed we are the second-most efficient company in the sector on waste, bioresources, and retail. In fact, in retail, we received more than GBP 50 million more than we had in our original plan.
As a reminder, thanks to our outstanding status, these base costs can only go higher between draft and final. Altogether, base costs are around 10% higher than they were in AMP7 in real terms, reflecting the higher actual costs experienced by the whole sector in AMP7 that are now built into those historical models. However, the biggest driver of our increased TOTEX is enhancement spend, which is four times the size of PR19. The majority of this enhancement spend is also determined through cost models, and as in the case of base costs, we've outturned favorably in those, with 93% of that spend that is modeled approved. The areas where our spend is yet to be approved are those without established cost models, which are naturally harder to assess, and Ofwat requires more evidence to support the costs we've included in our plan.
The great news is we have loads of evidence to provide, thanks to our significant pool of in-house expertise and all of the learnings we've gained through our AMP7 program, including our unique green recovery program. We are looking forward to submitting that evidence as part of our DD response in August, which we anticipate will increase our investment program even further. We recognize the importance of making as much investment as quickly as possible to deliver benefits to our customers, to the environment, and of course, our shareholders, who help us to finance them. Of course, while it's fantastic to have the DD now, when we were writing our plan, we were confident we were looking at a significant step-up in investment, much of which was underpinned by statutory obligations.
That's why we went to the market last year and raised GBP 1 billion to support the AMP8 program, which is something Ofwat has, have recognized in their determination. Thanks to that decision and the support of our shareholders, our balance sheet is already brilliantly positioned to fund this growth, giving us the ability to accelerate GBP 450 million worth of investment to get ahead of our AMP8 program and address priority areas such as storm overflow spills at a super fast pace.
...On returns, as expected, the WACC has increased between Ofwat's early view and the draft determination, which will be the minimum return for us due to our outstanding status, which also provides an extra 30 basis points, taking our return on equity to 5.1%. We've also seen some positive changes in the methodology for calculating cost of debt. I'm really pleased to see the 15 basis point halo effect previously applied to the new cost of new debt allowance has been removed, more accurately reflecting the reality of market conditions. We also see the potential for additional changes to increase cost of debt further. For example, the allowance for the cost of embedded debt doesn't yet include the actual cost we've seen across the sector for 2023/2024 financial year, and we would expect these to reflect higher rates experienced in the last 12 months.
We will, of course, be including cost of debt in our discussions with Ofwat, and we look forward to having this confirmed by Ofwat in December this year with the publication of the final WACC. And now Shane will touch on ODIs.
Thanks, Helen. Ofwat remain firmly committed to incentivization through ODIs, which of course, we're big fans of at Severn Trent, having been the consistent leader since their inception. In its draft determination, Ofwat set out four key ambitions that they wanted to deliver on with regards to ODIs, which we're, of course, fully supportive of. They want ODIs to be more common, allowing for greater sector comparability. They want to set achievable but stretching targets. They want to make sure that there are risk protections in place. Finally, they want to provide powerful incentives to really drive performance, providing benefits for customers and the environment. To deliver these ambitions, Ofwat have made some changes to the ODI landscape, and there are a few key differences we wanted to highlight today.
We've got far fewer ODIs to focus on, but they are common across the sector, which means relative performance will be really critical, and we feel really in good shape in that regard. Now, there are a few new ODIs, but we're pretty familiar with them already. Things like biodiversity, which has been a bespoke ODI for us throughout AMP7, albeit with a slightly different measure. And the rewards and penalties on offer are more valuable to really push companies to deliver a step change in performance, especially on those big totemic issues like leakage, where the incentive is almost three times greater than it was in AMP7. And as you'd expect, improved service for customers has been the real focus area for Ofwat in the price review. Another has been bills and affordability, which I'll touch on now.
As Liv mentioned earlier, we're looking forward to multiple AMPs worth of significant investment and growth, so it's really vital that we're focused on doing everything we can to keep bills affordable whilst delivering improved service. Coming into this price review, we already had one of the lowest bills in the sector, and the good news for our customers is that despite almost GBP 12 billion of investment, we still have the second lowest bill in England and Wales in 2030. And to put that into context, today, our bill makes up about 1.2% of disposable income for the median household on our patch, and it will still be 1.2% in 2030. But customers will be receiving even better service, greater resilience to supply services in a significantly improved environment, which our research tells us is something they care deeply about.
We know there are some customers who aren't in a position to pay, and we don't want any customers living in fear of their water bill. We remain firmly committed to eradicating water poverty by 2030, and to support that goal, we've got a GBP 575 million package of support. That means we can offer support to one in six of our customers. We're also trialing new ideas to help customers with their bills. For example, rising block tariffs enabled through our extensive smart metering program and the implementation of the Kraken billing platform. Finally, we'll be increasing the support we provide through our community fund, which is an important part of our broader societal strategy as we aim to tackle the long-term drivers of poverty on our patch.
Just before I hand back to Liv, it's worth quickly mentioning our Welsh water company, Hafren Dyfrdwy . HD has achieved a standard rating, gaining an extra five basis points on the cost of equity, and it had over 90% of its enhancement expenditure accepted. That investment level is its highest ever, and it will deliver a real RCV growth of 32%, adding further value to the group. To sum up, I'll hand back to Liv.
So thanks, Helen. Thank you, Shane. And let me now summarize what we've talked about today. So a lot of the draft determination was exactly as we'd expected and we've been talking about for some time. We thought we submitted a good plan, and Ofwat agrees and has given us that lovely outstanding rating. We expected an increase in the WACC, and that's come through. We were confident that our base costs would rank as efficient across the sector, and that's true, and we've also proven the need for significant step-up in investment, which is also reflected in our draft determination. So we're now going to be delivering our highest ever RCV growth rate in AMP8, with much greater certainty of investment needs right out to 2050.
Of course, we've done all of the hard yards to get our balance sheet into great shape to be able to deliver this investment. That means that we are now going to be delivering much needed investment for our customers that will also benefit the environment. Of course, we see opportunities to gain further upside between now and the final determination. Don't forget that our WACC and our base costs can only go up from here, and we're confident in our ability to evidence increased TOTEX, which will give us a really good platform for ongoing discussions through now and the nineteenth of December. That was meant to be a whistle-stop tour through the facts of the DD, but of course, you're bound to have questions.
We look forward to answering those, the three of us later, at either 2:00 P.M. or 10:00 P.M., depending on where you are in the world. So we look forward to seeing as many of you as possible dialed in for some Q&A later today. Thank you for listening.