Residential Premises

Industrial Entities

Public Sewer
Discharge Permit

Preliminary inspections and other guidelines such as the amount of flow, impacting characteristics of the wastewater, type of process, and regulations are taken into consideration to determine if a business is required to have a Public Sewer Discharge Permit.

Public Sewer Discharge Permits are issued (but not limited) to:

Food Packing Plants

Industrial Laundries

Rendering Facilities

Poultry Processors

Bottling Companies

Food Processors & Mfg


Metal Finishers


Industrial Bakeries

Pharmaceutical Companies

Fuel Service Stations



Elderly care homes


Vehicle mechanics/panel beaters/sprayers

Carpenters/Aluminium/Glass workshops

Petroleum products storage & processing

Injection moulding facilities

Electronics Mfg plants


Farms (Chicken/pig/cow)

Slaughter Houses

Permits to discharge into the sewer contain a series of administrative requirements and discharge conditions that the users must comply with at all times. Permits are given for a one year period, are tailored to each user with applicable conditions and are not renewed automatically.

Click here for more information about sewage treatment considerations and requirements.

Keeping Harmful Substances Out

goal of applying for and obtaining a Public Sewer Discharge Permit is to keep
harmful substances out that could:

•Damage sewer systems (through blockages), pumps and treatment plant structures;

•Interfere with biological treatment process operations;

•Jeopardize worker safety by exposure to chemical hazards;

•Reduce reusability potential of New Water due to contaminated effluent and issues with acceptability of biosolids when landfilling;

•Result in violations of the treatment facilities’ own Waste Discharge Requirements imposed by the Environmental Permits issued by ERA;

•Add maintenance, repair, operational and disposal costs to the treatment of wastewater;

Treatment considerations

Trade effluent generated by industrial entities generally requires some form of treatment. This can range from a simple sedimentation tank to a fully fledged biological treatment plant as illustrated below:


The objective of a sedimentation tank is to remove readily settleable solids and floating material and thus reduce the suspended solids content.



Oil / Water Seperator


A full retention oil/water separator is based on the principle of separation by gravity, the lighter oil and fuel rises to the top while the heavier sludge and sediment settles at the bottom. Clean wastewater then flows out which can be safely discharged into the wastewater system. Full retention interceptors have a specialised float seal which as soon as the oil or fuel reaches the opening to the float chamber, this seal closes and stops water from flowing. It will only resume flowing once the oil or fuel is cleaned out of the chamber. Such interceptors are mandatory to be installed in fuel service stations, car wash stations, and any areas where wastewater can be contaminated with traces of petroleum hydrocarbons. Contaminated waters from the cleaning of oil/water separators must be collected and disposed of by approved treatment facilities.

Treatment of Catering wastewaters

Any catering establishment that prepares food must have a grease trap in order to retain the fats and greases released during washing of pots, pans and other tableware.

There are 3 principal types of grease traps:





A Mechanical grease trap actively removes greases through a mechanically-operated skimming wheel and deposits the waste oils in an external container. These types of units require daily cleaning of the solids collection basket, monthly desludging (sludge not to be disposed to sewer) and annual maintenance.


Physical (Gravity) grease traps use the principle of physical separation by slowing the flow of water inside the trap. This allows fats and greases to become buoyant and to separate. These traps are generally housed below ground and require frequent (once-twice a month) cleaning – depending on the size and load. It is important that the waste cleaning contractor used for cleaning disposes of the oily layer appropriately (i.e. not discharged to sewer). After cleaning, it is important that the grease trap is refilled with water.


A biological grease trap uses a biological agent to degrade the fats and greases present in the wastewater. This requires frequent periodic dosing of an additive generally by the use of a peristaltic pump. Dosage shall be as per manufacturer’s instructions. These types of units require daily cleaning of the solids collection basket, monthly desludging (sludge not to be disposed to sewer), and replacement of additive depending on load and dosing frequency.

Prohibited equipment/treatment systems

The following items are prohibited from being used:


Under-sink food grinders


Macerating equipment for non-biodegradable materials such as bed pads and nappies


Water Softener (unless regeneration reject water is discharged to sea)

Wastewater macerating pumps (for non-domestic use)

How to apply

The process entails filling in the application form and payment of an €11.65 fee. Alternatively, you can use our online portal to register.

Here’s a step by step procedure to help you register online

The fee is applicable only for new applications or other applications that are not renewals (amendment of permit). Secondly, for a new application, we ask the applicants for the following documentation including:

•site plans, internal drains layouts, Material Safety Data Sheets, and any operational permits/licenses the applicant holds with other authorities (such as MTA);

•In case of renewals we also ask for receipts of maintenance/cleaning of treatment facilities and also waste transfer receipts for the movement of wastes which are not authorised to be discharged to sewer;

As part of the permitting process, the entities may also be asked for an analysis of the trade effluent. Sampling guidelines are imposed by the DPU following the review of the documentation submitted and the on-site inspection/s.

At the end of the process, the DPU will issue the permit for a period of one year which is not renewed automatically. Industrial entities are advised to send their application for renewal of their permit at least one month before expiry.

Public Sewage Discharge Permit

To apply for a public sewage discharge permit kindly download the required form

English – Maltese – Privacy Notice

Enforcement Actions

Regulations are enforced through actions that could  escalate from simple Warning Notices to Criminal Court Cases if discharges constitute a public health and safety issue.

Compliance through pollution prevention measures instead of enforcement actions is highly preferred. Increasing facility inspections by DPU inspectors have played an active role in improving the visibility of the legal requirement to obtain a Public Sewer Discharge Permit and also enhanced communication with the various industries and the overall number of permits compliance rate in the last four years.

Planning Applications initial vetting / Clearances

The Water Services Corporation is one of the consultative bodies in relation to planning applications submitted to the Planning Authority. In this respect, the Corporation is asked to give its feedback at the initial vetting stage and also after construction is complete during the compliance clearance stage. This applies to both residential and industrial/non-residential developments.

WSC’s requirements aim to safeguard its water and wastewater infrastructure from a physical point of view during the construction phase, by ensuring that all preparations are undertaken if provision of services are required. Moreover, WSC’s requirements also aim to prevent misuse of the wastewater network, including any illegal rainwater connections and the disposal of unauthorised materials into the sewer system. For compliance clearance requests, the Corporation may also request a physical inspection of the premises to verify compliance with the stipulated conditions.

To apply for a No objection or clearance from the Water Services Corporation, kindly follow the link below to submit your request:

If you have a specific query or would like further information kindly send an email to

In doubt? Contact DPU

If you need further information about the discharge of waste water into sewer, you can contact the Discharge Permit Unit by phone on 2244 3184 or by e-mail on