Frequently asked questions

Storm water

1. Why is the disposal of storm water so costly?

Considerable costs are involved in the drainage and treatment of storm water. As opposed to wastewater, where the quantities are subject to minor fluctuations during the day only, storm water falls in irregular quantities and intervals. During load peaks of sometimes only a few minutes the wastewater quantity can be exceeded by far. For the sewage it means adaptation in terms of size and capacity. The dimensions of wastewater sewers are far too small.

2. What is the calculation basis for storm water?

The charge of storm-water fees is governed by the statute of Stadtentwässerung (sewage fee statute). Pursuant to Art. 10, para. 1 of this statute the sewage fee depends on the area to be assessed. The area, on the other hand, is determined by the directives of Art. 10, para. 2 and 3. Depending on the type of surface sealing and use of the area concerned, different assessment values are applied. Thus, the individual fee charged should be as fair as possible. Included in the calculation are all areas from which storm water is directly or indirectly brought into municipal sewers.

3. Will storm-water fees also be charged when such water flows over short distances into public sewage systems and then untreated into waters?

Yes, also in this case, there is an obligation to pay. For the charging of fees and the amount it is not important whether the storm water flows into a sewage treatment plant or into a receiving water course. Decisive for fair fees is whether or not municipal sewers are used. Costs are also incurred when the water is brought into receiving water. Such costs are allocated to the storm water on the solidarity principle. The construction and operation of storm-water retention tanks and the payment of sewage fees concern all fee payers.

4. Do I also have to pay storm-water fees if I am legally required to seal the premises?

Storm-water fees must also be paid in this case. Even special conditions cannot be granted. According to the present law, the sewage fee statute for compulsory sealed premises do not need not make exceptions or hardship clauses. Since the larger area does in fact create higher expenditures for the discharge and treatment of storm water, there is no possibility to waive such fees.

5. Are factors such as the amount of rain or leap year relevant for the storm-water fee?

Since the storm-water fee is charged on an annual basis it does not matter how many days there are in a year. The basis of calculation is exclusively the forecasted annual average cost. Thus, the amount of rain water per year is also irrelevant.

6. Will the storm-water fee be discarded if it is collected in a cistern and used for plant watering?

The existence of a cistern is of no relevance for the charging of the storm-water fee. Decisive is whether or not the cistern is connected to municipal sewers (e.g. by an overflow). But in no case does the garden watering result in a waiver of a storm-water fee. In principle, the full amount of the storm-water fee has to be paid, even if part of the rainwater is used for plant watering and is not discharged into public sewers. The technical expenses incurred for the storm-water discharge is mainly determined by the cost of provision. The drainage systems have to be dimensioned so that they are capable of discharging the storm water during any time of the year. Such expenses are also incurred if less water is discharged for a short period of time (during summer through garden watering).

Exceptions may only be granted if the technical facilities ensure that little amounts of rain water are discharged throughout the year. The sewage fee statute takes care that built-up or paved areas with a connection to retention facilities and secured by an emergency overflow to the sewage system, may be granted fee reductions according to Art. 10 of the above statute. Such an installation could be a cistern in which the storm water is collected throughout the year and whose content is used as process water. A cistern of 5 m³ useful storage volume reduces the built-up area by approx. 67 m², provided it is used all year round.

7. Why are there separate fees for wastewater and storm water?

In 1987 the mixed fee was replaced by separate fees for wastewater and storm water. With the introduction of separate fees the City responded to the court rulings by the Federal Administrative Court which require that a common fee for wastewater and storm water may only be charged if the share of the connected properties in storm water does not exceed 15 % of the total cost of property drainage (wastewater and storm water).

A common fee would not have distributed the actual input involved fairly. The disposal of storm water incurs considerable costs. The larger the property area (e.g. roofs or parking lots) the less exact the rating of the mixed water based on water consumption would be. This would be unfair to property owners whose rainwater seeps away or who have only few sealed areas. A mixed fee would mean that everyone would share the total cost of storm water disposal on the basis of solidarity. An unfair system. The extent to which public utilities are used needs to be taken into consideration when the fee calculation is done (principal of equivalence).

No hidden fee increase took place with this change in fee calculation. When calculating the wastewater and storm-water fees, merely the portion of costs of the present mixed water fee was split up. All in all the citizens were not faced with more burdens. In fact, property owners who let their storm water seep away or who used it, were considerably unburdened.

Fee assessment notice

8. Can a fee assessment notice be issued or rectified retroactively?

In principle the answer is yes. A retroactive assessment of the drainage-effective area is possible.Even if a fee assessment notice has been given and it has attained legal force, there is no obstacle to change such notice subsequently. However, this requires that facts are made known, making the basis on which such notice was given appear incorrect. Pursuant to Sect. 48 of the Administrative Procedures Act (VwVfG) an unlawful administrative act can, even after it has become final, be wholly or partially revoked with effect for the future or past.

Charging sewage fees

9. To what extent can sewage fees be charged retroactively?

Pursuant to the municipal rates act (KAG) the assessment period for sewage fees is four years. Within this period fees can be charged subsequently, provided that there was an obligation to charging. If no fees were charged over a longer period of time, this will not constitute confidence protection. In such a case forfeiture will not apply.
Fees may also be charged retroactively for rented apartments. Since the landlord has to settle the running cost accounts with his tenants (Sect. 556, para. 3 of Civil Code) annually, there is no obstacle to claim fees subsequently from the landlord. It is the landlord´s responsibility that the time limits are complied with. Through complete and correct statements of the sewage fees, one has to create the preconditions for fee charging in a timely manner. In case of outstanding accounts landlords may reserve the right to subsequent charging in the running cost statement. Should such an exception not be explained, the fees have to be paid to the local authority. Should the landlord not be able to allocate the additional running costs to his tenants retrospectively due to this default, then this will be his responsibility.

Payment of fees

10. What will happen if I am unable to pay the fees?

If one is not able to pay the full fees or only a part of the amount, then one has the possibility to apply for payment by instalments. To be able to check the preconditions (applicant’s need and eligibility) for granting a deferment of payment, one has to present a detailed reason for the application, a contemporary and detailed summary of the personal and economical relations as well as a realistic payment plan with securities.

Additional costs

11. Who will bear the additional costs incurred for obtaining information on the drainage system for my property?

It is generally the property owner who has to bear the costs for obtaining such information. A right to the reimbursement of costs does not exist. With such information the property owner meets a duty incumbent on him. Neither will he be called upon as a witness or expert nor will he act on a third party´s behalf.

Sewer construction

12. Can I claim compensation if my property cannot be accessed by car due to sewer construction works?

Such compensations will not be provided by the legislator. In principle all efforts are made when construction measures are planned in order to avoid nuisances which may be caused by adjoining property owners. If short-time access restrictions become inevitable, property owners are not entitled to any kind of compensation.
The legally protected use of property refers only to an adequate road connection. Only in the case of commercial properties it must be ensured that the property can be safely and properly accessed by trucks. Private owners have the right to request parking facilities on public roads and spaces in close vicinity to their property. The adjacent owner use will not be affected should customer parking lots be abolished due to a change in traffic guiding. To what extent such restrictions have to be accepted in each individual case depends on the relevant public requirements. It is basically sufficient if the property can be accessed on foot whilst the construction works are on. According to the legislation, access by car is not necessary. Even a decline in sales resulting from construction works has to be accepted, without compensation if such construction is inevitable.

Sewer at my property

13. If the exact location and elevation of the sewer in front of my property are not known, do I need to find out this information?

As property owner you are obliged to do so. For a proper operation of the municipal sewage system it is not necessary to survey all installations with respect to their height and location. Although exact data on elevation and location are available for most of the sewer systems it may be possible that some sewers can only be determined approximately. In such cases it will be the owner’s responsibility to arrange all necessary investigations for a connection. The right to obtain information exists only insofar as the data is already known. The project owner does not need to undertake any further investigations which are not necessary from the operational point of view.


14. Is it possible to use pre-treated water from a septic tank to water the garden?

The use of pre-treated sewage for plant watering is contradictory to the water act, the building code and hygiene. Pursuant to Sect. 32 of the State Water Law (LWG) any sewage, sludge from septic tanks and the content of septic tanks must be left to the party who has the duty to dispose of the sewage or his agent. This also applies then, when the sewage of a septic tank with downstream plant bed has been pre-treated. The courts are of the opinion that the usage of sewage for watering the plants may influence water management issues. Sewage may penetrate into the ground water through the soil. In addition public health my be threatened. Domestic sewage contains different kinds of pollutants, even after pre-treatment (permanent stages of parasites, pathogens, such as bacteria, viruses, worm eggs) that can only be eradicated by heating or special filter techniques. Chemical substances from cleaning and washing agents are considered to be additional risks. They, too, can not be completely eliminated by multi-chamber septic tanks incl. plant bed (soil filter).

15. Is one allowed to cover the inspection manhole with soil and plant on it?

No, it is under no circumstances allowed. To ensure proper operation of municipal sewers it is necessary to aerate the sewers sufficiently. Otherwise it may lead to fouling and formation of explosive gases. Ventilation openings are therefore inevitable and prescribed by the statute. Another point is the accessibility of the inspection manhole. In order to be able to respond quickly in emergencies, any blocking, covering or disguising must be avoided.