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Summary and conclusions

Background and scope of project

Earlier analyses have shown that owners of plots for houses that are contaminated, or previously were contaminated, may have to bear larger costs in connection with lending, or they suffered a larger loss resulting from depreciation of their property than other house owners. However, the data material has not been sufficient to allow general conclusions on the magnitude of loss.

Such conclusions have been attempted in connection with work in the Land Depreciation Committee, which resulted in the establishment of the Land Depreciation Programme, and, finally, in connection with the evaluation.

The Danish EPA therefore initiated this study in 2004, in order to investigate the extent to which owners of contaminated sites, or sites that were contaminated previously, may have experienced a loss in connection with selling their property, or whether such contamination affects the possibility for potential buyers to raise loans in connection with buying the property.

This study analyses the depreciation loss, if any, experienced by owners of property that is or was contaminated in the period 1996-2003.

The study does not include the effect on the costs of mortgage loans on the property in connection with selling, since the mortgage banks do not register commitments or refusals of applications for loans.

The study is the first part of a land depreciation project. The second part will analyse the costs of removing residual contamination that may still remain.

Data collection

In the study, data from different data sets are coupled, i.e. data from environment databases and land registries, and data on market prices of properties, and public property valuations.

Environment data was collected from central databases/registers of contaminated sites in Denmark operated by the Danish EPA and the Agency for Governmental Management, while land register data was collected from these databases, and from the National Survey and Cadastre Denmark, and from the municipalities of Copenhagen and Frederiksberg.

Data on buying and selling houses was collected from the Central Customs and Tax Administration database of property valuations and the prices of houses on the market.

Data collection focuses on the following identification flow:

Identification of contaminated/previously contaminated sites -> identification of land belonging to the registered land -> establishment of unique list of registered land -> identification of contaminated properties that have been sold on the market -> identification of comparable properties, i.e. properties sold in the same valuation district -> establishment of unique list of traded contaminated/previously contaminated properties and non-contaminated properties -> delimitation of data to include only traded properties approved for permanent habitation/housing).

The collected data was integrated in a project database.

Key parametres

A pivotal issue in the study was the status of contamination of individual properties in the entire period 1996-2003.

A contaminated site may very well change its contamination status over time – from being suspected of contamination (knowledge level V1), to having an ascertained level of contamination (knowledge level V2), and later, to having been cleaned up or to being affected by residual contamination.

The project database was established by coupling data in the three central databases of contaminated sites, and setting up codes for eight contamination levels.

Table 0-1: Contamination status

Code Contamination status
1 Suspicion Specific suspicion of soil contamination
2 Contaminated Contamination ascertained
3 Cleaned up Contamination removed
4 Residual contamination Residual contamination after clean-up
5 Investigated, no findings Investigated without ascertaining contamination
6 Not contaminated Not related to contamination
7 Before registration Code is used in years prior to entering the property in database/registry
8 Information is missing No information on contamination status

The study measures the loss of value by quantifying the market price's share of the public valuation. The report defines this share as the relative market price (RH)[2].

The study also applies the concept of free trade, which differs from trade within the family, sale by auction, and other types of trade. Free trade means sale/purchase of properties between parties with opposing interests regarding the market price, while for other types of transactions, a number of unknown factors may influence the market price.

Project database

In order to establish a unique database, data was prioritised in two ways.

1) Where property transactions involved contamination data derived from more than one database/one registry, the data was prioritised accordingly.

Information from the source databases was ranked by order of priority, in order to make sure that correlations were unique.

Information from the OM (Danish Oil Industry's Association for Remediation of Retail Sites) database ranks highest, then the VTO (Land Depreciation Programme) registry, and last, information from the national register of contaminated sites ROKA.

The order of priority was also defined for transactions related to several “registered properties”, i.e. localities in ROKA, cases registered in the OM database or the VTO register with different codes identifying the contamination status.

Where transactions are related to several registered properties having different contamination statuses, the worst-case status was given the highest priority. Prioritisation is shown in Table 0-2.

Table 0-2: Prioritisation of contamination status in project database

Priority1 Contamination status
7 2 Contaminated
6 1 Suspicion
5 4 Residual contamination
4 3 Cleaned up
3 5 Investigated without findings
2 7 Before registration
1 8 Information is missing
0 6 Not contaminated

1Highest number = highest priority

The project database includes at total of 693,160 transactions, of which 7,756 are related to registered properties which at the time of sale were listed in one of the three central databases of contaminated and possibly contaminated sites (suspicion, contamination, cleaned up, residual contamination, and investigated without findings).

Of these, the number of free transactions with complete transfer of title to the property is 6,925. These transactions form the basis for the statistical calculations made in this study.

The number of transactions indicates that the data used is very well suited for a more detailed analysis of the magnitude of the depreciation loss.

Public property valuation reduction recorded by the Customs and Tax Administration

The number of transactions of contaminated sites with complete transfer of title to the land (i.e. not only to part of the land) in free trade (i.e. not within the family, and not by auction), where the Customs and Tax Administration has recorded reduced valuation, is 3,328. Of these transactions, reduced valuation due to contamination was recorded in 179 transactions.

Frequency of properties being resold

Properties in the project database have been resold approx. 1.25 times on average in the period 1996-2003. The frequency for non-contaminated properties is 1.3.

Statistical analysis

The data was processed statistically in variance analyses, which contribute to determining the importance of different factors to the relative market price and to determining whether differences are incidental.

Five hypotheses were set up to reveal the factors that influence the loss of value.

Hypothesesis 1: There is a relationship between the relative market price of the property, its contamination status, and the area in Denmark in which the property is located.

Hypothesis 2: There is a relationship between the relative market price of the property, its contamination status, and the zoning of the site (urban or rural zoning).

Hypothesis 3: There is a relationship between the relative market price of the property, its contamination status, and the type of housing (detached house, flat etc.).

Hypothesis 4: There is a relationship between the relative market price of the property, its contamination status, and the programme under which the contamination is managed (Contaminated Soil Act, Danish Oil Industry's Association for Remediation of Retail Sites (OM), or the Land Depreciation Programme (VTO)).

Hypothesis 5: There is a relationship between the relative market price of the property in connection with resale and a change of the contamination status of the property.

The statistical analyses are based on an iterative approach, starting by setting up a statistical model, scrutinising of the data material (incl. test running), revision of the model, and finally, final running and interpretation of results.

Prior to each running of a model analysis, extracts of transactions were made from the project database, using a number of general and, sometimes, model-specific criteria.

The general criteria were:

  • Transaction on the free market
  • 100 per cent transfer of title to the property
  • Market price and valuation above 0
  • Contamination status 1-6.

Among the hypothesis-specific criteria were:

  • Code identifying area in Denmark
  • Zoning code
  • Land use code
  • Code identifying database/scheme.

Further, non-deviating observations were to be made. Statistical tools were used in order to select deviating observations.

The analyses were based on a 10 per cent level for the variance analysis model, and a 90 per cent mean value confidence level.

The assumptions for variance analyses, including the requirement for independent observations (transactions), normally distributed residuals (normality), and variance homogeneity, are fulfilled for all model hypotheses with sufficient convergence to carry out the statistical analysis.

Table 0-3 shows the data basis after filtering.

Table 0-3: Data basis used in Hypotheses 1-5

Contamination status Hypothesis 1
Area in Denmark
Hypothesis 2
Zoning
Hypothesis 3
Land use
Hypothesis 4
Scheme
Hypothesis 5
Resale
1. Suspicion 2,367 1,857 2,292 2,367 18-29
2. Contaminated 2,439 1,844 2,411 2,439 22-40
3. Cleaned up 643 570 629 643 46-63
4. Residual contamination 548 433 538 548 63
5. Investigated without findings 240 203 230 240 29
Total Contamination status 1-5 6,237 4,907 6,100 6,237 -
6. Not contaminated 558,806 503,563 547,870 558,806 -

Results

Results of the five model runnings are presented in figures and tables for the five hypotheses. The figures show the share of the purchase price (market price) of the valuation. The tables show the loss of value in percentage points in relation to non-contaminated sites.

Hypothesis 1 (area in Denmark)

Figure 0-1: Hypothesis 1 - Contamination status and area - estimated RH values for transactions, and 90 per cent confidence interval distributed by contamination status.

Table 0-4 Hypothesis 1 – Loss of value due to contamination, in percentage points

Contamination status 1) Suspicion 2) Contamin. 3) Cleaned up 4) Residual contamin. 5) Investigated without findings
Category
Copenhagen + surr. - - - 10.2 9.7
Zealand/Funen 5.4 - 4.5 - 6.3
Jutland 5.0 3.3 4.2 - 6.4

”– ”: no significant deviation from non-contaminated sites.

The analysis shows:

  • significant differences between areas in Denmark,
  • contamination status ”suspicion” causes larger loss of value than ”contaminated” and “cleaned up”,
  • contamination status ”contaminated” results in significant loss of value only in Jutland,
  • contamination status ”cleaned up” does not differ significantly from ”contaminated”,
  • contamination status ”residual contamination” only causes significant loss of value in Copenhagen and surroundings,
  • contamination status ”investigated without findings” causes more than 6 percentage points loss of value.

Hypothesis 2 (Zoning)

Figure 0-2: Hypothesis 2 - Contamination status and zoning - estimated RH values for transactions and 90 per cent confidence interval distributed by contamination status.

Figure 0-2: Hypothesis 2 - Contamination status and zoning - estimated RH values for transactions and 90 per cent confidence interval distributed by contamination status.

Table 0-5: Hypothesis 2 - Loss of value in percentage points caused by contamination in relation to non-contaminated sites

Contamination status 1) Suspicion 2) Contamin. 3) Cleaned up 4) Residual contamin. 5) Investigated without findings
Category
Urban zone - - -2.5 6.0 5.6
Rural zone 10.7 - - - -

”– ”: no significant difference.

The analysis shows:

  • significant differences between urban zones and rural zones,
  • contamination status ”suspicion” is not significant in urban zones, but causes significant loss of value in rural zones,
  • contamination status ”contaminated” does not cause significant differences in the relative market value,
  • contamination status ”cleaned up” causes significant increase of value in urban zones,
  • contamination status ”residual contamination” causes significant loss of value in urban zones, while the loss in rural zones is considerable, but not statistically significant,
  • contamination status ”investigated without findings” causes significant loss of value in urban zones, while the loss in rural zones is considerable, but not statistically significant.

Hypothesis 3 (Use of house)

Figure 0-3: Hypothesis 3 - Contamination status and use of house - estimated RH values for transactions and 90 per cent confidence interval distributed by contamination status

Figure 0-3: Hypothesis 3 - Contamination status and use of house - estimated RH values for transactions and 90 per cent confidence interval distributed by contamination status

Table 0-6 Hypothesis 3 Loss of value in percentage points caused by contamination

Contamination status 1) Suspicion 2) Contamin. 3) Cleaned up 4) Residual contamin. 5) Investigated without findings
Category
Detached house 7.7 3.0 3.2 3.5 7.3
Flat 3.2 - - 10.4 12.1

”– ”: no significant difference.

Based on these categories, the figure and table show:

  • significant differences between the categories,
  • contamination status ”suspicion” results in significant loss of value in both categories,
  • contamination status ”contaminated” results in significant loss of value in the category ”detached house”, ’while the loss of value for the category ”flat” is neither relative nor significant,
  • contamination status ”cleaned up” results in significant loss of value in the category ”detached house”, while the loss of value for the category ”flat” is neither relative nor significant,
  • contamination status ”residual contamination” results in significant loss of value in both categories, largest for flats,
  • contamination status ”investigated without findings” results in significant loss of value in both categories.

Hypothesis 4 (Scheme)

Figure 0-4: Hypothesis 4 - Contamination status and scheme – estimated RH values for transactions and 90 per cent confidence interval distributed by contamination status

Figure 0-4: Hypothesis 4 - Contamination status and scheme – estimated RH values for transactions and 90 per cent confidence interval distributed by contamination status

Table 0-7: Hypothesis 4 - Loss of value in percentage points caused by contamination

Contamination status 1) Suspicion 2) Contaminated 3) Cleaned up 4) Residual contam. 5) Investigated without findings
Category
OM 2.6 5.3 --- --- 8.1
ROKA 5.5 -3.1 - 5.6 6.9
VTO --- - -8.8 6.3 ---

”– ”: no significant difference.

Considerable differences are found between the three databases, which do not include comparable categories for all levels of contamination. The categories are compared to the average relative market value for the contamination status ”not contaminated” in the same public valuation district.

With this division of categories, the figure and table show that:

  • contamination status ”suspicion” causes a significant loss of value (OM, ROKA),
  • contamination status ”contaminated” causes a significant loss of value (OM), a modest but significant increase of value (ROKA), while the result for VTO does not differ significantly,
  • contamination status ”cleaned up” results in significant increase in value (VTO),
  • contamination status ”residual contamination” results in a significant loss of value (ROKA, VTO),
  • contamination status ”investigated without findings” results in a significant loss of value (OM, ROKA).

Hypothesis 5 (Resale)

Click here to see Figure 0-5

Test of:

  • Hypothesis 5a (suspicion to contaminated) did not show significant difference between categories.
  • Hypothesis 5b (suspicion to investigated without findings) showed significant difference between categories.
  • Hypothesis 5c (contaminated to cleaned up) did not show significant difference between categories.
  • Hypothesis 5d (contaminated to residual contamination) showed significant difference between categories.

Conclusions

The study shows that hypotheses 1-4 are substantiated:

  • Hypothesis 1: There is a relationship between the relative market price of a property, its contamination status, and the area in Denmark in which the property is located.
  • Hypothesis 2: There is a relationship between the relative market price of a property, its contamination status, and the zoning (urban or rural zone).
  • Hypothesis 3: There is a relationship between the relative market price of a property, its contamination status, and the type of property involved (detached house, flat etc.).
  • Hypothesis 4: There is a relationship between the relative market price of a property, its contamination status, and the scheme under which the contamination is managed (Contaminated Soil Act, the Danish Petroleum Industry's Association for Remediation of Retail Sites (OM), or the Land Depreciation Programme (VTO).

However, the study shows that Hypothesis 5 is only partially substantiated:

  • Hypothesis 5 (partially): There is only a relationship between the relative market price of the property in connection with resale, when the contamination status changes from ”suspicion” to ”investigated without findings ”, and from ”contaminated” to ”residual contamination”.

The study shows that property owners may achieve considerable gains by having their site investigated in cases where the contamination status is changed from “suspicion” to ”contaminated”.

It should be noted that contamination in relation to flats will often be associated with problems in the indoor climate.

The study also shows that the Land Depreciation Programme is an efficient tool, enabling the owner to achieve considerable gains by cleaning up the site, because the loss of value is reduced.

The historical development of the data registers used, and the geographical development in the process of mapping contaminated sites may both contribute to deviations from what is expected for some of the results. One of the reasons is that the price of properties has increased very much in the period 1996-2003. The price increases in the period do, however, vary considerably, both geographically, and among different types of properties.

It is important to note that the analysis was made in a period (1996-2003), in which the real estate market has developed rapidly, and the lack of dwellings may in certain areas have influenced the relative market price for properties affected by contamination.

Looking at the loss of value expressed as DKK per DKK 1 mill. (valuation), the study reveals the following average loss of value for the five different levels of contamination:

  • Contamination status 1 – Suspicion: DKK 57,000
  • Contamination status 2 – Contaminated: DKK 21,000
  • Contamination status 3 – Cleaned up: DKK 1,000
  • Contamination status 4 – Residual contamination: DKK 70,000
  • Contamination status 5 – Investigated without findings: DKK 78,000

The study also shows that the actors on the housing market are confident that the sites have been cleaned up. The loss of value for transactions related to the contamination status ”cleaned up” amounts to DKK 1,000 per DKK 1 mill. (valuation).

However, it also appears that any form of uncertainty, whether it is based on facts or not, i.e. for contamination statuses suspicion, contaminated, residual contamination or investigated without findings, will be reflected in the price.


Fodnoter

[2] Relative market price (Relativ handelspris (RH)) = market price (valuation + any price reduction due to contamination). Section 2.3.3 gives a more detailed description of RH.

 



Version 1.0 November 2005, © Miljøstyrelsen.