The Hurunui District Council occasionally tests the districts sewers with smoke, we call this "smoke testing". Smoke testing involves pumping smoke into the sewer system and keeping track of where it emerges.
This testing is a method used to find breaks and defects in the sewer system. It also shows where storm water and other surface water may be entering this system.
Smoke testing is common practice and helps keep faults to a minimum and unnecessary water out of the sewers - which in turn makes treating wastewater more efficient and cost-effective.
The “smoke” we use is actually a vapour and is the same non-toxic substance used in smoke machines at concerts. It is considered safe for humans, animals and plants, leaves no residue or stains and will disappear rapidly without leaving an odour.
Before each new round of smoke testing, we notify the residents who may be effected. We do this by:
- Sending a letter to all houses in the area selected for testing
- Placing information in the newspaper or local newsletters
- Posting on community Facebook groups
Frequently asked questions below:
How does smoke testing work?
During smoke testing, crews blow air and smoke into the sewer system through manholes. The smoke fills the main sewer pipe and any connected pipes, and follows the path of any leak to the ground surface. Crews monitor where smoke escapes the system to find the leaks.
What are the benefits of smoke testing?
Smoke testing is the most efficient and cost-effective way to find leaks and areas that need improvement in the sewer system. It also helps to identify plumbing leaks that may allow harmful sewer gases to enter buildings.
In addition, smoke testing helps to find where storm water and other surface water gets into the sewer system. Keeping unnecessary water out of sewers makes treating our wastewater more efficient and cost-effective.
Is the smoke harmful to me or my pets?
No. The "smoke" is not true smoke. It is a harmless white vapour which is safe for humans, animals and plants. It leaves no residue or stains, is not a fire hazard, and will disappear rapidly without leaving an odour.
Since any vapour can be an irritant, direct contact with the smoke may cause minor respiratory irritation in some people. People with respiratory problems such as chronic asthma or emphysema should avoid direct exposure to the smoke. Please contact the council to discuss your situation further if you have concerns about upcoming smoke testing.
Will the smoke get into my home?
Smoke appearing in your home may indicate that there is a problem with your plumbing. We suggest you contact a licensed plumber to inspect and make necessary repairs if you see smoke in your home during our testing.
For example, If your plumbing is installed and working properly, and you will have “U traps” filled with water that will prevent smoke entering your home.
A “trap” is a U-shaped section of your drain pipes. It is designed to fill with water to stop sewer gases getting into your home through sinks and drains (see image). If there is no water in the trap, it will not work properly.
Dry traps are most often found in floor drains and bathroom drains that are used rarely. Please thoroughly check your home. We recommend running some water into building drains and fixtures before smoke testing.
What does it mean if smoke enters my house?
If smoke enters your home during the test, there may be problems with your plumbing, we recommend you contact your plumber immediately.
If you have any doubt as to the source of the smoke in your home or property and suspect a fire, please call 111 immediately.
How may smoke enter my house?
Because your plumbing is connected to the sewers, smoke may enter your home or workplace if:
- Vents connected to your building's sewer pipes are inadequate, defective, or improperly installed
- Traps under sinks, tubs, basins, showers and other drains are dry, defective, improperly installed, or missing
- Pipes, connections and seals of the wastewater drain system in and under your buildings are damaged, defective, have plugs missing, or are improperly installed.
What should I do if smoke gets into my house?
- Do not be alarmed.
- Open windows to allow ventilation and note where the smoke is coming from; it will clear in a few minutes.
- Leave your home and notify smoke testing personnel in the area. This is precautionary until we confirm that the smoke is from our testing and is not indicative of fire.
- If smoke enters your home during the test, there may be problems with your plumbing. These problems could allow potentially dangerous sewer gas to enter. Please contact your plumber immediately.
If you have any doubt as to the source of the smoke in your home or property and suspect a fire, please call 111.
What should I do to prepare for smoke testing?
- Check all drain traps contain water by running some water into building drains and fixtures before smoke testing. A “trap” is a U-shaped section of your drain pipes. It is designed to fill with water to stop sewer gases getting into your home through sinks and drains (see image). If there is no water in the trap, it will not work properly. Dry traps are most often found in floor drains and bathroom drains that are used rarely.
- Flush all toilets and pour water into all drains, including unused fixtures and floor drains.
- If there is an individual in your home or business with respiratory problems and/or mobility limitations, or if you have any additional questions, contact Gerry O’Neill on 06 366 0999.
How will i know if smoke enters my house if I am not home during the testing?
Smoke testing focuses on the public part of the sewer system, which Council maintains. While the test also helps to identify plumbing problems on private property, this is not the main intent of the smoke test. It is the homeowner’s responsibility to maintain private plumbing connections. Please contact your plumber if you have any concerns about plumbing on your property.
Why can't you tell me in advance exactly what date my home will be tested?
We can’t do smoke testing when it’s rainy or very windy, so the weather can sometimes cause delays. Also, other activities in the project may take less time than expected, so it can sometimes be sooner than expected. However, we will let you know the period in which we will be smoke testing your area by mail.
Can the smoke testing activate smoke alarms?
Yes, smoke alarms may be activated during smoke testing. If possible, open windows and/or doors for ventilation. If you have any doubts about the origin of the smoke, call 111.
Can smoke plug the sewer?
No need to worry, the smoke is a vapour and cannot plug the sewer.
Where does the smoke appear?
Smoke will be seen coming from roof vents on homes. This is normal and indicates that smoke has filled the sewers. Smoke may be seen coming from building foundations, manhole covers, or yard cleanouts.
What happens after the smoke testing is completed?
Council will use the findings to help plan future public infrastructure improvement projects and to identify changes required to stop storm water and other surface water from getting into the sanitary sewer system. Depending on the findings, we may also undertake immediate repairs to the sewer system.