[Revised entry] The Netherlands stopped being able to take drinking water for granted around 2022, when businesses began to be refused connections to the mains. The public health institute put a number on the gap: 102 million cubic metres more will be needed in 2030 than in 2020. The minister answered with three strategies, and the Court of Audit examined one of them - using less water. It found targets that are measurable and widely supported, which is more than can usually be said of a policy target, and then went looking for the machinery that would tell anyone whether they are within reach: milestones, evidence on what businesses do with a quarter of the water, an evaluation of a tax break worth EUR 110 million a year, a count of the connections refused. 102 million m³ more drinking water needed in 2030 than in 2020 household target: 119 litres per person per day in 2023 down to 100 litres in 2035 business target: 20 percent below the 2016-2019 reference period, 239 million m³ against 299 million m³ households 72 percent of consumption (812 million m³ in 2021), businesses 28 percent (314 million m³) showers and toilets: more than 76 of the 119 litres a person uses each day €1.7 billion - turnover of the ten designated drinking water companies in 2023 €110 million - revenue forgone in 2025 through the mains water tax ceiling dozens of businesses refused a connection since 2022 Drinking Water Act Government Accounts Act 2016, sections 7.16 and 3.9 Order on Periodic Policy Evaluations 2022 EU water resilience strategy National Drinking Water Action Plan Water Availability Action Programme 2023-2030 Decree on construction works in the living environment (BBL) the mains water tax ceiling and the revenue forgone cost and benefits of compulsory rainwater and greywater systems price elasticity of drinking water evaluation of a tax regulation that statute requires to be evaluated pace of policy-making from the 2019 evaluation to the 2024 action plan use made of commissioned studies milestones between present consumption and the 2035 targets fit between the housebuilding programme and the timetable for compulsory saving systems feasibility of the household target feasibility of the 20 percent reduction for business consumers effectiveness of behavioural measures and the awareness campaign insight into what businesses use drinking water for information on the consequences of shortages The audit opens by crediting the minister: he 'has set measurable targets that have the backing of many parties, including local authorities, industry associations and drinking water companies, which is to be applauded. A minister's targets are not always measurable and do not always enjoy such support' (p.9). What is missing is everything between today and 2035. 'It is doubtful whether the minister will achieve his household water saving target. Furthermore, he has not set milestones to gauge progress towards the target' (p.12), and he 'has also failed to explain whether he expects drinking water consumption to fall gradually or abruptly. The savings expected by, say, 2030 in order to meet the 2035 target are therefore not known. This should have been thought through in advance in order to adapt policy where necessary' (p.13). The evidence that would fill the gap was commissioned and then left unused: the minister 'has commissioned studies of the potential benefits of compulsory rainwater or greywater systems and of the pricing system for drinking water. But he has not used the results to check whether he is on course to achieve the targets. The studies' implications for the targets are accordingly uncertain' (p.13). A goal-setting weakness of a particular kind - the destination is defined precisely and the route is not defined at all. The minister has since accepted the recommendation, undertaking to include milestones in the mid-2026 update of the action plan (p.18). Households account for 72 percent of consumption and 'the greatest gains are to be made by reducing household consumption, which accounts for nearly three-quarters of all drinking water consumption in the Netherlands' (p.9); showers and toilets together take more than 76 litres of the 119 a person uses each day (p.10). To move that number 'the Minister of I&W is seeking a change in behaviour and greater water-awareness in construction projects. He is working on a national water awareness campaign. It is difficult to predict how effective measures to change behaviour will be' (p.11). Two commissioned studies point the same way: one 'concluded that the public had only a limited sense of urgency regarding drinking water shortages', another 'found that drinking water had very low price elasticity, which means a modest price increase would have little effect on consumption' (p.11). The fall since 2022 that brought the target closer is not clearly the policy's doing either - the audit attributes it partly to shorter showers taken in response to high energy costs and to wet summers (p.6). The strategy rests on the one instrument whose effect the audit says cannot be predicted, and on a price signal that the minister's own evidence says will not work. A large share of household water flushes toilets, so 'the use of rainwater or greywater could potentially save a lot of drinking water', and the minister 'regards housebuilding as an opportunity to save drinking water. Fitting the many houses that have to be built with a rainwater or greywater system would make a significant contribution to the saving targets' (pp.11-12). The timetable works against the opportunity: 'the housebuilding programme commenced in 2021 and it will take many years, until 2028 at the earliest, before all studies are completed and the regulations (the BBL) are amended' - so 'many houses will already have been built if and when such systems become compulsory' (p.12). Three separate doubts sit on top of the timing. The systems 'might come with detrimental effects to public health', a study for the minister 'found that rainwater and greywater systems were very expensive', and a deregulation programme run by another minister 'to scrap conflicting and unnecessary rules and so reduce the regulatory burden on housebuilding' makes it 'far from certain whether a new compulsory measure will be introduced' (p.12). In its afterword the Court of Audit urges the minister to continue the studies and to base compulsory measures on their findings (p.19). Business consumption carries a 20 percent reduction target and is the one line on the chart moving the wrong way: 'business consumption has risen' and 'for business users, the gap between consumption in the reference period and the target has actually widened rather than narrowing' (pp.3, 7). The causes 'are not entirely clear' (p.6). Nor is the remedy: 'the Minister of I&W has no information on the possible effectiveness of incentives offered to business customers to save water. As too little is known nationally about what businesses in diverse sectors are using drinking water for, effective incentives cannot be identified and the feasibility of the 20% reduction target is uncertain' (p.13). What is known points at waste that could be designed out - a research institute 'found that companies use water of drinking water quality in processes that do not require drinking water', manufacturing being the heaviest user, especially food and chemicals (p.13). The minister's answer is to await scans by the drinking water companies; the Court of Audit accepts that these can find savings in an individual business but notes 'it is uncertain whether promising measures will be identified for specific sectors at national level' (p.19). A target is set for a population the policy-maker cannot yet characterise. Mains water tax is charged on the first 300 m³ a customer uses and not above it, so 'in practice, business customers do not pay tax on the water they use in excess of the ceiling' - which makes the ceiling 'in effect ... a tax scheme for businesses', with the Ministry of Finance estimating the revenue forgone in 2025 at EUR 110 million (p.13). The obligation is unambiguous and unmet: 'in the past 25 years, the mains water tax ceiling has never been evaluated, even though evaluation is compulsory. The Minister of I&W therefore has no insight into its efficiency and effectiveness' (p.13), and the Court of Audit restates the legal basis in its afterword - 'periodic evaluation of tax regulations is required under the Government Accounts Act and the Order on Periodic Policy Evaluations 2022' (p.19). The evidence that does exist runs against using the instrument for savings at all: a 2024 report to parliament 'concluded that an increase in mains water tax or the tax ceiling would probably have little or no effect on water savings', yet the minister said he was considering raising the ceiling 'to prevent waste and for budgetary reasons' (p.13). The Court of Audit closes the thread with an observation about how such obligations end: after the audit, the State Secretary for Finance announced a bill to abolish the ceiling, and 'if it no longer exists, of course, neither will the obligation to evaluate it' (p.19). Shortage has already arrived in a concrete form - 'in 2022, business customers in several parts of the Netherlands were refused new drinking water connections' - and it had not been foreseen: an evaluation of the previous policy period in 2019 'qualified the rising demand for drinking water as being of "limited urgency"', so that 'the Minister of I&W did not foresee the drinking water shortages in the intervening 3 years. It is remarkable that the minister makes long-term water security plans but does not anticipate fluctuations in demand in the relatively short term' (p.14). Three years on, the events still are not counted: 'the minister does not know how often drinking water companies refuse to connect business customers. Nor does he know which and how many housebuilding projects might be cancelled or delayed because they cannot be connected to the water mains' (p.14). The exposure is known in outline - a 2022 sector map shows that 'housebuilding is planned chiefly in areas where security is already under pressure' - and the ministry 'admits that it does not collect information on the consequences of drinking water shortages, even though it would strengthen the minister's ability to anticipate the societal consequences of shortages and inform parliament about them' (p.14). An information gap chosen rather than suffered, on the one question a parliament would ask first.