Factsheet: the effect of deposit return schemes on litter

Alongside older measurements from the United States (1970s and 1980s) and Denmark (2017), recent monitoring results from the Netherlands (2018–2022) now also show that the introduction of a deposit return scheme sharply reduces the number of beverage containers in litter.

Litter data United States (1970s and 1980s)

In the 1970s and 1980s, the states of New York, Iowa, Maine, Michigan, Oregon and Vermont in the United States conducted, or commissioned, studies that mapped the impact of deposit schemes on litter by counting the number of cans and bottles at the same locations before and after the introduction of a deposit.

A federal analysis by the U.S. Government Accountability Office concluded that these studies were conducted independently and thoroughly by the various states, and together are useful for assessing the effect of deposit return systems on litter. The methodologies of the studies are not entirely identical, but are comparable.

These studies showed that introducing a deposit on beverage containers led to a decrease of approximately 70-84% (in numbers) of the relevant beverage containers in roadside litter. The total amount of litter decreased as a result by 30 to 45%.

Research consultancy CE Delft used these results in their study Costs and effects of a deposit system on small bottles and cans (2017) to estimate the effects of a deposit scheme on the amount of bottles and cans in litter. CE Delft summarised the results of the American studies (see table below).

Litter data Denmark (2008-2017)

Data has also been collected in Denmark showing that a deposit scheme has a significant reducing effect on the presence of deposit containers in litter.

CE Delft (2017) concluded that in Denmark, a deposit led to a reduction of 70-90% of deposit cans in litter. It refers to three different Danish sources that provide insight into the proportion of cans in litter with and without a deposit. These reduction rates are in line with the American results from the 1970s and 1980s.

Explanation for the presence of non-deposit cans in Denmark

Even though Denmark has had a deposit on cans since 2002, there were (predominantly) non-deposit cans in litter. This mainly concerned cans from shops just across the border in Germany, which sell packaging with special labels that do not carry a German (or Danish) deposit. According to data, the ratio between cans with and without a deposit in Denmark is therefore 50/50. The number of German containers (without deposit) placed on the market amounts to around 600 to 700 million according to a press release from the Law Office. This number is roughly equal to the number of deposit cans reported by Dansk Retursystem (650 million units).

Annual clean-up and counting campaign by volunteers (2016)

In Denmark, a large group of volunteers annually collects and counts cans from litter. In doing so, they distinguish between cans with and without a deposit. CE Delft (2017) refers to what was then the most recent count in 2016. That year, a total of more than 100,000 cans were picked up, of which 23% were cans with a deposit and 77% were cans without a deposit. CE Delft (2017) calculated that, assuming equal consumption volumes of Danish and German cans, the likelihood of Danish cans ending up in litter is a factor of 3.3 lower than German cans without a deposit (77%/23%). This would correspond to a reduction rate of approximately 70%.

Calculation: suppose 77 cans initially end up in litter, then after the introduction of a deposit, there are only 23 cans left. This is a reduction of 54 cans. This corresponds to a reduction rate of approximately 70% (54/77 is 70%).

Data from Dansk Retursystem (2014)

Dansk Retursystem, the system operator of the Danish deposit system, presented to CE Delft that in the year 2014, 80% of the cans in litter were cans without a deposit. CE Delft concluded that according to this data, the likelihood of a can without a deposit becoming litter is 4 times higher. This corresponds to a reduction rate of 75%.

Calculation: suppose 80 cans initially end up in litter, then at this ratio, there would be 20 after introduction. This is a reduction of 60 units (80 minus 20) or 75% (60/80 is 75%).

Measurements by Danmarks Naturfredningsforening (2008-2017)

CE Delft received measurement data for the years 2008-2018 from Danmarks Naturfredningsforening, the organisation that supervises the annual counts. During this period,

a total of 1,520,781 cans were picked up, of which 162,995 carried a deposit (and therefore 1,357,786 were without a deposit). This amounts to roughly 90% of the cans in litter being non-deposit cans. According to this data, the likelihood of a can becoming litter is 9 times higher when there is no deposit on it. CE Delft calculated that this corresponds to a reduction rate of approximately 90%.

Calculation: Before introduction, 90 cans end up in litter; after introduction, this falls to 10 at this ratio. The decrease is 80/90 or (rounded) 90%.

Dutch deposit study CE Delft (2017)

Research consultancy CE Delft investigated the effect of a deposit scheme on the amount of bottles and cans in litter in the study Costs and effects of a deposit system on small bottles and cans (2017). For this, they analysed the aforementioned data from the United States and Denmark. Based on these figures (and calculations based on CE Delft's own survey from 2001), CE Delft based their expectation that “a deposit reduces the number of cans and bottles in litter by 70 to 90%”.

Litter data Netherlands (2016–2022)

Litter monitoring as part of policy agreement

On 10 March 2018, then State Secretary Stientje van Veldhoven announced that she would introduce a deposit on small plastic bottles containing water and soft drinks, unless the business community succeeded by autumn 2020 in (a) recycling 90% of small plastic bottles and (b) reducing the share of plastic bottles in litter by 70-90%. The 70-90% reduction in litter was based on expected results of a deposit from the CE Delft report (2017), and thus the measurements from the United States and Denmark.

In light of the performance agreement regarding litter reduction, a monitoring programme was set up. Rijkswaterstaat reports every six months on the number of plastic bottles in litter. They started with the first half of 2018. From the second measurement (covering the second half of 2018), RWS also counted the number of cans in litter and included this in the reporting. From the report on the first half of 2019, Rijkswaterstaat also includes the measurements of ‘Zwerfinator’ Dirk Groot in their report. Rijkswaterstaat and Dirk Groot each use their own methodology.

Deposit is introduced, monitoring continues

When Rijkswaterstaat's report in April 2020 showed that the industry would not succeed in reducing the proportion of plastic bottles in litter by at least 70% before autumn 2020 (the number of plastic bottles in the environment had increased by 7%), then State Secretary Van Veldhoven decided early on 24 April 2020 to introduce a deposit on small plastic bottles containing water and soft drinks from 1 July 2021.

Recycling Netwerk Benelux urged at the time that monitoring by Rijkswaterstaat of the number of bottles should continue after the introduction of the deposit on these beverage containers. In this way, new figures would emerge providing insight into the effect of a deposit on the number of beverage containers in litter. This was agreed.

First results after introduction of deposit (second half of 2021)

The first results following the introduction of the deposit on 1 July 2021 concerned monitoring for the second half of 2021. On 3 January 2022, ‘Zwerfinator’ Dirk Groot announced that his research showed the proportion of small plastic bottles in litter had fallen since the introduction of the deposit. In the final quarter of 2021, he recorded 70.2% fewer plastic bottles per kilometre than the average of the final quarters of 2017, 2018, 2019 and 2020.

Rijkswaterstaat’s report for the second half of 2021 (dated 15 February 2022) was published on 5 April 2022. This report shows that in the second half of 2021, Rijkswaterstaat counted 41% fewer small plastic bottles in litter than in the second half of 2020.

Please note: a deposit was introduced on small plastic bottles of soft drinks and water. As a result, several other categories of small plastic bottles fall outside the deposit scheme, such as dairy and juices. In both of the above measurements, the reduction percentage was measured across all small plastic bottles.

The 70.2% reduction as measured by Groot relates to the fourth quarter, and the 41% reduction as measured by Rijkswaterstaat covers the third and fourth quarters of 2021. The margin in the results can be explained, among other things, by the fact that in the third quarter there were still many non-deposit bottles in litter and (old) non-deposit bottles were still being sold. Producers are given time to sell off their old stock without a deposit. Furthermore, Groot also cleans up the counted beverage containers in the litter during his measurements, which prevents them from being counted across multiple surveys. Rijkswaterstaat merely counts and leaves the beverage containers behind. As a result, ‘old’ bottles, still without a deposit, can reappear multiple times in counts. This flattens the reduction percentage somewhat.

Results one year after introduction of deposit (first half of 2022)

On 12 September 2022, ‘Zwerfinator’ Dirk Groot published his report with monitoring results up to and including the first half of 2022, one year after the introduction of the deposit scheme. In this report, Groot calculates the reduction percentage for plastic bottles within the category on which a deposit is levied: soft drinks and waters. His measurements show that 76% fewer plastic bottles containing water and soft drinks ended up in litter.

This percentage by Groot is already focused on the water and soft drink category. However, the measurement is still ‘polluted’ by non-deposit bottles. Consider, for example:

old water and soft drink bottles that ended up in litter before the deposit was introduced and are still lying there;

• water and soft drink bottles purchased abroad without a deposit;

• water and soft drink bottles sold (illegally) in the Netherlands without a deposit;

• bottles whose labels have disappeared (and were recorded by Groot as ‘without deposit’).

It goes without saying that the deposit measure cannot have an impact on these non-deposit bottles – and that they should therefore not be counted to measure the actual effect of the deposit. 

This most recent monitoring report from Groot is particularly valuable because, in his counts within the soft drink and water category, he makes the additional distinction between plastic bottles with and without a deposit. His measurements show that the number of plastic bottles for soft drinks and water in the environment with a deposit is now 1 per km, whereas for that same group of beverages without a deposit it was previously 6.9 per km. The actual deposit effect in the Netherlands therefore amounts to 85% fewer plastic bottles in the environment.

Rijkswaterstaat's report for the first half of 2022 is still pending.. Groot's dataset will again be included in this. 

Relevant changes in the Dutch deposit system for plastic bottles

There are two important notes to make regarding the monitoring results for the first half of 2022. According to the deposit legislation, a deposit must be levied on plastic bottles containing water and soft drinks. In practice, this exempts other drinks, such as juices and dairy, from the deposit legislation. 

On 24 January 2022, the Human Environment and Transport Inspectorate (ILT) ruled that plastic juice bottles with added water and sugar also fall under the deposit scheme, because these drinks legally classify as a soft drink. This decision came in response to an enforcement request from Recycling Netwerk, which noted in November 2021 that until that time many drinks of this type (such as nectars, (fruit) juice, and multivitamins) were on the shelves without a deposit. The business sector was given 3 months to correct this error. In practice, this means that from April 2022 deposits are levied on more bottles, because deposit legislation was complied with better from that point onward. This means that the fraction of bottles that ends up in litter less often thanks to deposits has grown. 

On 2 February 2022, Statiegeld Nederland opened the deposit system to plastic bottles containing 100% juice. Drinks consisting of 100% juice are still not subject to deposit legislation, but juice producers can voluntarily participate in the deposit system from that date (if the bottles meet the conditions for recycling as stated by Statiegeld Nederland). This opening means that a deposit can be levied on more plastic bottles. Albert Heijn announced on 12 May 2022 that it would start charging deposits on all 100% juice bottles under the Albert Heijn brand. It is unclear how many producers are now charging deposits on their drinks and therefore how large the proportion of juices is that now carries a deposit. In his most recent report, Groot indicates that while a decrease in the number of juice bottles in litter can be seen in the first half of 2022 (-22%), this falls within the range of deviations in previous years. 

Monitoring in the Netherlands (cans)

From the second measurement (for the second half of 2018), Rijkswaterstaat also includes the number of cans in litter in its monitoring. The most recent measurement by Rijkswaterstaat for the second half of 2021 shows an increase of 21% in cans in the environment. This stands in sharp contrast to the observed 41% decrease in bottles from the same Rijkswaterstaat report. 

From 31 December 2022, a deposit will also be levied on cans. The monitoring report for the first half of 2023 will therefore also provide insight into the effect of the deposit on the share of cans in litter.