How often does the holding tank need to be emptied?

It depends on usage and tank size. A level alarm gives warning before the tank is full, so it does not overflow. Emptying is done by a vacuum tanker, ideally under a fixed emptying agreement.

Holding tank for wastewater: sealed tank where wastewater cannot be discharged

Q: What is a holding tank?

A holding tank (sealed tank) is a closed, watertight tank that collects wastewater from a property where it is not permitted or possible to discharge to the ground or the sewer network. The tank is emptied by a vacuum tanker as needed.

Q: When do I need a holding tank?

When the property lacks a public sewer connection and is located in an area where infiltration or discharge is not permitted, for example near drinking water sources or in sensitive areas. Sealed tanks are common for cabins and holiday homes.

Short answer: A holding tank (sealed tank) is a closed, watertight tank that collects wastewater where it is not permitted or possible to discharge to the ground or the sewer network. It is emptied by a vacuum tanker as needed, and a level alarm gives warning before it is full. Sealed tanks are common for cabins and properties in sensitive areas.

01What is a holding tank?

A holding tank, often called a sealed tank, is a closed container that collects all the wastewater routed to it, without any discharge to the ground or watercourses. The water is stored until the tank is emptied by a vacuum tanker. Because no treatment or discharge happens locally, it is absolutely essential that the tank is completely watertight. Norrloop supplies sealed tanks in rotationally moulded polyethylene (PE).

02When do you need a holding tank?

A sealed tank is relevant where wastewater can neither be infiltrated nor discharged to the sewer network:

Properties without access to a public sewer
Sensitive areas, for example near drinking water sources or in catchment areas
Ground that is not suitable for infiltration
Cabins and holiday homes with limited or seasonal use

The local authority decides what is permitted on the individual property, so the solution should be clarified with them early.

03Blackwater or all wastewater?

A sealed tank can be set up in two ways:

Solution	Receives	Note
Blackwater only	Toilet water	Greywater from the shower and kitchen is routed to a separate solution. Smaller tank volume and less frequent emptying.
All wastewater	Blackwater + greywater	Simpler setup, but larger volume and more frequent emptying.

What is permitted and recommended depends on the local authority's requirements and the consumption on the property.

04How large a holding tank do I need?

The size is determined by the consumption and how often the tank is to be emptied. A cabin with few users and blackwater only needs far less volume than a home that collects all wastewater. Norrloop sizes the tank to the usage pattern and a practical emptying frequency.

Consumption

number of users + use

Year-round home or cabin, blackwater or all wastewater.

Emptying frequency

how often a vacuum tanker

Less frequent emptying requires a larger tank.

05Level alarm prevents overfilling

A sealed tank must never overflow. It is therefore fitted with a level alarm that gives warning in good time before the tank is full, so you have time to order emptying. The alarm is a cheap insurance against accidents and odour, and is often a requirement.

06Emptying and operation

The tank is emptied by a vacuum tanker. Most people choose a fixed emptying agreement, so that emptying happens regularly without having to keep track of it yourself. Make sure there is good access for the vacuum tanker and that the manhole cover is easily accessible.

07Why a sealed tank in PE?

For a sealed tank, full tightness is the most important thing, and here polyethylene is a good material. PE is corrosion-free and leak-tight, with no joints that can fail the way concrete elements can, and no risk of rust the way steel has. That gives a safe, long service life in the ground.

PE material

leak-tight

No discharge to the ground. Corrosion-free, long service life.

Light

easy handling

Easier to transport and lower into place than concrete.

08Frequently asked questions

What is a holding tank?

A closed, watertight tank that collects wastewater where it is not permitted or possible to discharge to the ground or the sewer network. The tank is emptied by a vacuum tanker as needed.

When do I need a holding tank?

When the property lacks a public sewer and is located in an area where infiltration or discharge is not permitted, for example near drinking water sources. Common for cabins and holiday homes.

Does the tank collect all wastewater or only toilet water?

Both are possible. A sealed tank is often used only for blackwater, while greywater goes to a separate solution. What is permitted depends on the local authority's requirements.

How often does the tank need to be emptied?

It depends on usage and size. A level alarm gives warning before the tank is full, and emptying is done by a vacuum tanker, ideally under a fixed agreement.

Do you need a sealed tank?

Norrloop sizes and supplies a holding tank with a level alarm tailored to the property and the local authority's requirements.