A pressure sewer system uses small-diameter pipes and grinder pumps installed at each home. The sewer lines are buried just below the ground and follow the contours of the land ("up and down" hills or a constant grade across flat land, for example).

The grinder pump station collects all of the wastewater from the home and grinds it into slurry. The wastewater is then pumped to a wastewater treatment plant or system, a gravity manhole, a larger sewer main or to a septic system.

Christchurch's wastewater network was heavily damaged by the Canterbury earthquakes, prompting the city to explore more resilient alternatives to traditional gravity sewers. Pressure sewer systems proved to be an effective solution for many areas due to their reliability, flexibility and suitability for local ground conditions.

Unlike gravity sewers, pressure sewer networks use small-diameter, fully sealed pipes that can be installed at shallow depths without the need for a continuous downhill gradient. This makes them ideal for areas with high groundwater, flat terrain, difficult ground conditions or where deep excavations would be costly and disruptive.

Because the network is sealed, pressure sewers also help reduce groundwater and stormwater entering the wastewater system, improving environmental performance and reducing the risk of wet-weather overflows.

Today, thousands of Christchurch properties are connected to pressure sewer systems, making them an established and important part of the city's wastewater infrastructure.

Ecoflow is a New Zealand specialist in pressure sewer technology, providing the design, supply, installation, commissioning, monitoring and ongoing maintenance of pressure sewer systems. We work with councils, developers, engineers and homeowners to deliver reliable wastewater solutions that are suited to challenging ground conditions and modern infrastructure requirements.

Our team has been involved with pressure sewer networks in Christchurch since the city's post-earthquake wastewater rebuild, helping deliver one of New Zealand's largest pressure sewer deployments. Over the years, pressure sewer technology has become an established part of Christchurch's wastewater network and continues to support both existing communities and new developments across the region.

Christchurch City Council owns and operates the public wastewater network that serves the city. Ecoflow supports that network by providing specialist expertise in the pressure sewer infrastructure that connects many properties to the wider council wastewater system.

Our role includes:

• Responding to service requests and faults to help keep systems operating reliably.

• Supporting Christchurch City Council's pressure sewer operations and maintenance programmes.

• Assisting developers and consulting engineers with the design and delivery of new pressure sewer networks.

• Providing homeowners with technical support, education and guidance on how to get the best performance from their system.

While most residents rarely need to think about their pressure sewer system, Ecoflow works behind the scenes to ensure wastewater is transported safely and reliably from homes and businesses into Christchurch's wider wastewater network.

With thousands of pressure sewer connections now operating throughout Greater Christchurch, Ecoflow's experience, local presence and specialist knowledge help support the long-term performance and reliability of this critical infrastructure.

The grinder pump station is the heart of the pressure sewer system. The station is comprised by three main components:

• Grinder Pump - this is a purpose built pump designed to macerate and pump wastewater.

• Collection Tank - the tank captures all the wastewater from the property. The tank contains the grinder pump and is sized to provide storage.

• Alarm Panel - this device is mounted on the side of the house and provides an interface for the user or service provider. It also will notify you in the event service is required.

The E/One grinder pump station supplied by Ecoflow is designed to operate as a cohesive unit. It has the longest track record and largest installation base in New Zealand and globally.

All of the wastewater from the home (from toilets, sinks, dishwasher, washing machine, etc) flows by gravity into the tank. When wastewater reaches a certain level, the pump turns on automatically and pumps the wastewater to the sewer main. As it pumps the wastewater, it draws through a grinding mechanism, turning it into a slurry. The pump will turn off automatically.

Do not flush wipes, oil, grease, paint, strong chemicals, sand, kitty litter, etc. down your drain. Feminine products and personal/cleaning wipes should be disposed of in a garbage can. These items should not be flushed into any sewer or septic system. They can damage your pump or build up in the tank and prevent your pump from working properly.

If the alarm turns off after a few minutes and does not turn on again, the grinder pump should be OK. Check regularly to ensure that the grinder pump is operating and the alarm is not on.

If the alarm turns on and off repeatedly or turns on and stays on, call an authorised service center for service. Discontinue water use to avoid causing a backup or overflow.

Look on your alarm panel for a service sticker with a phone number. When in doubt, contact Ecoflow for guidance.

Pressure sewer systems with grinder pump stations are a type of wastewater collection system. There are many other types of wastewater collection systems.

Pressure sewers and grinder pumps are also used regularly when a single or group of properties are below the level of a new or existing wastewater system (like a gravity system) and cannot easily connect.

Ultimately, pressure sewer system and grinder pump systems are environmentally friendly and efficient methods to provide wastewater service to residential and commercial areas. The systems help keep groundwater and stormwater out of the sewer system and therefore reduce the likelihood of environmental or public health issues during wet weather events. Thanks for keeping our water supply and beaches clean!

A typical single family home uses less than 700 litres of water per day. The average estimate is 2.7 persons at 220 litres/person/day or 594 litres per day. The grinder pump operates at approximately 0.7 litres/second or 42 litres per minute. The E/One grinder pump consumes on average 0.6kW while running. The E/One will use between 9 and 20 kWh per month (60-240 kWh per year). Check your utility bill for the cost per kilowatt hour in your area. For example, if you pay 25 cents per kilowatt hour: $0.25 KWh x 120 KWh = $30.00 per year cost of electricity to operate the E/One pump.

It depends on the ownership model of the pressure sewer system. The ownership model is typically dictated by the local council or water authority.

When systems are publicly owned, like most system in Christchurch, the council or water authority is responsible for the costs to maintain the grinder pumps. This has economic and logistic benefits for all stakeholders.

Sure! But first, make sure you own the system before making any cosmetic modifications. It's important to ensure that no paint gets inside the grinder pump station (that can create environmental issues) or you don't impact the ability for the tank to vent.

As a point of information, most system components in the E/One systems supplied by Ecoflow use polyethylene and other similar robust plastic materials. Paint may not adhere very well to these surfaces.

Properly installed and operating private drainage (designed and installed in accordance to AS/NZS 3500) should not allow internal fixtures to overflow. The overflow relief gully (or gully trap) is specifically designed to prevent an overflow inside of a house due to downstream sewer issues.

If your sinks, toilets, etc. are overflowing, it is due to a restriction or blockage inside the house or before the grinder pump station. Consult a plumber for more help.

The button on the bottom of the panel is used to silence the audible alarm of the panel.

If the audible alarm sounds, there might be an issue with the system. Follow the instructions or give Ecoflow a call for help.

It depends on the type of the panel. The silence button is typically on the top right corner or the bottom left corner of the exterior of the panel enclosure. Pressing the button once should silence the alarm.

The alarm panel has four toggle style latches (one on the top and bottom, and two on the side). The panel may also have a padlock to prevent unauthorised access. Finally, there may be screws in the top and bottom right corners of the panel enclosure door.

Please note - caution must be taken when opening the alarm panel. There may be live or active electrical connections inside the panel. Only authorised users should access the panel.

Other alarm panels (e.g. OneBox) require a specialised key to open.

Sure! As long as any planting does not obstruct the gap around the lid and the lid does not become a low point, you can integrate the tank into your landscaping.

In order for free flowing drains, the tank must be vented. The tank lid features integrated venting. Ensure you don't obstruct the venting while landscaping.

The area around the tank and the alarm panel will need to be accessed by service technicians periodically. If there are obstructions, it may prevent them from accessing your equipment and providing service.

Ecoflow recommends you DO NOT build any permanent or semi-permanent structures around the alarm panel or tank lid. Anything obstructing access will need to be removed prior to the service technician responding to the site. The service technicians cannot move these items for you.

Thanks in advance!

Since the system only operates when water is being used, it is unlikely that the system will operate or go into alarm while you're not home.

Oftentimes, an unattended site that is in alarm will be noticed by a neighbour who can silence the alarm and ring the service agent (or you - if you're friendly with your neighbour). Alternatively, with the Sentry Protect Plus alarm panel, the audible alarm can be configured to automatically silence after 10 minutes. Though - Ecoflow do not recommend this setting in most cases.

A properly operating system should not smell. If you can smell the system, something may be wrong and it might be best to have a service technician check it out.

One exception may be if the system has not been used for a long period of time (4+ weeks). It is possible that the retained wastewater in the system may have gone septic. You usually won't notice until you return and start using water again. If that's the case, the odour will typically disperse after a short period of time with regular water use.

If you are leaving for an extended period of time, it's best to flush the system with clean water (e.g. fill a bath) before departing. Also - it's best to leave power on to the system even if you plan to be gone for a period of time.

If the alarm panel is located somewhere normally inaccessible or you are concerned you won't hear the alarm, there are remote alarm options available.

Ecoflow can offer wired and wireless (cellular) remote alarm systems to give you peace of mind.

As a reminder - a properly installed and operated E/One system should not require regular maintenance.

It is not recommended to install the alarm panel inside the home or garage.

The service technician will need access to the alarm panel if a repair is required.

The alarm panels are weatherproof and designed to be installed outside in the elements. This also enables the technician to access the panel without disturbing you.

Globally, council ownership of pressure sewer systems is most common. Councils are able to leverage economy of scale and specialised maintenance teams to ensure the system is operated as efficiently as possible.

When systems are privately owned, it is typically due to the council overestimating the complexity of operating the systems. However, specialists companies (like Ecoflow) are available to help users when service or repair is required.

Ecoflow are not involved in the decision making process regarding who owns the grinder pump and who is responsible for maintenance costs. Contact your local government representative if you need help with the existing ownership policy.

Repair costs will vary based on the complexity of a potential fault. For units that Ecoflow services directly (those in the greater Auckland and Christchurch regions), Ecoflow charges a fixed $250 (incl GST) call out fee which covers travel and the first hour of diagnostics/repair on site. Additional costs may be required beyond that if components of the system need to be repaired or replaced.

The BEST thing you can do to reduce repair costs is to keep wipes, fat, grease, and other debris OUT of the system.

All wastewater systems operate best when they receive the "3 P's" - pee, poo, and paper.

There is nothing that you shouldn't flush down a grinder pump station that you also shouldn't flush down a gravity sewer.

Keep those wipe out of the pipes! And also, ensure you are dumping cooking oils and grease into the bin and not down the sink.

You have the power to ensure the wastewater system and the costs to operate the system are efficient as possible! Thanks in advance

In general, there is no regular operations and maintenance required on a E/One system. The best thing you can do is keep debris out of the system – only water, pee, poo, and paper should be in the system. Check out the Ecoflow Homeowners guide for more information.

If you have access to your Alarm Panel, you may be able to monitor or check on the condition of the system. There are a few different versions of Alarm Panel so make sure you are referring to the correct instructions.

Check out the Ecoflow Pump Controllers page for more detail.