Identify illegal connections and infiltration issues with professional smoke testing services across New Zealand's North Island.
Smoke testing provides a fast, non-invasive method to detect defects in sewer and stormwater systems. TDG Environmental's experienced operators use advanced smoke testing equipment to pinpoint illegal connections, leaks, and infiltration points that compromise your network's integrity.
Undetected defects in your drainage network create serious operational and compliance challenges:
Illegal Stormwater Connections – Stormwater entering sewer systems increases treatment costs and overloads capacity during heavy rain, risking overflows and environmental contamination.
Infiltration and Exfiltration – Groundwater entering damaged pipes (infiltration) or wastewater leaking out (exfiltration) compromises system efficiency and threatens public health.
Unknown Network Defects – Cracks, broken joints, and open access points remain hidden until smoke testing reveals their exact location.
Compliance Risks – Councils and asset owners manage networks to protect environmental outcomes under the Resource Management Act 1991, requiring regular assessment and maintenance.
Without regular diagnostic testing, these issues escalate into costly emergencies, environmental incidents, and regulatory breaches.
TDG Environmental conducts systematic smoke testing to identify defects in both mainline and domestic sewer and stormwater systems across the North Island.
Before commencing works, our operators conduct site-specific risk assessments to identify and mitigate all potential hazards. Safe Work Method Statements guide every aspect of the operation, ensuring compliance with the Health and Safety at Work Act 2015. The testing area is clearly delineated to protect public safety, and affected properties receive advance notification.
Our team opens manholes at both ends of the targeted section and blocks the line with inflatable test plugs to contain the smoke and direct it through the system. Using the Cherne Sealed Manhole Smoke Test Machine, we inject non-toxic smoke into the sewer or stormwater network. The smoke follows the path of least resistance, emerging at any defect points, illegal connections, or damaged sections.
As smoke is introduced into the system, our experienced inspectors systematically survey the testing area. Smoke plumes emerging from household connections, roof downpipes, ground surface cracks, or other unexpected locations indicate defects requiring attention. Each smoke leak is photographed, GPS-located, and documented with detailed descriptions.
Following completion of testing, TDG prepares thorough smoke leak reports that document every identified defect. Reports include defect descriptions, photographic evidence, and precise locations marked on council sewer plans. This documentation provides asset owners with clear evidence for remediation prioritisation and compliance records.
TDG utilises the Cherne Sealed Manhole Smoke Test Machine, which generates non-toxic, harmless smoke suitable for use in residential and commercial areas. The smoke is non-toxic and commonly used for drainage testing, dissipating quickly without leaving residue or odour.
With 30+ years of experience in New Zealand’s drainage industry, TDG’s operators understand the complexities of sewer and stormwater networks. Our team has conducted smoke testing across diverse environments, from urban residential areas to complex industrial sites, delivering consistent, reliable results.
Meticulous Safety Standards
Safety underpins every aspect of TDG’s smoke testing operations. Site-specific risk assessments identify potential hazards before work begins. Lines not being tested are blocked with inflatable test plugs to concentrate smoke in target areas. Testing areas are clearly marked and controlled to prevent public exposure. All work complies with Health and Safety at Work Act 2015 requirements.
Thorough Documentation and Reporting
TDG’s reporting provides asset owners with actionable intelligence for network management. Each smoke leak is documented with photographs, GPS coordinates, and detailed defect descriptions. Defects are marked on council sewer plans, creating permanent records that support maintenance planning, compliance obligations, and capital works programming.
Full North Island Coverage
Operating from multiple North Island depots, TDG provides responsive smoke testing services across Auckland, Waikato, Bay of Plenty, Hawke’s Bay, Taranaki, Manawatū-Whanganui, and Wellington regions. Our regional presence ensures fast mobilisation and local knowledge of council requirements.
Smoke testing identifies defects in sewer and stormwater systems by introducing non-toxic smoke into the network and observing where it emerges. This reveals illegal connections, cracks, broken joints, and infiltration points that would otherwise remain hidden. Councils and asset owners use smoke testing to locate stormwater entering sewer systems, identify network defects, and ensure compliance with environmental regulations.
TDG uses non-toxic, environmentally safe smoke that is commonly used for drainage testing. The smoke is specifically designed for drainage testing and dissipates quickly without leaving residue or odour. Residents may notice a slight smoke smell during testing, but it’s completely harmless and clears rapidly.
When smoke is introduced into a sewer system, it should only emerge from designated vents and access points. If smoke appears from stormwater drains, roof downpipes, or surface grates, it indicates an illegal connection between the stormwater and sewer systems. These connections cause stormwater to enter the sewer network, increasing treatment costs and risking overflows during heavy rain.
If smoke enters your property during testing, it indicates a defect in your household plumbing connections. This is a valuable finding, as it reveals problems like broken seals, missing traps, or faulty connections that could allow sewer gases to enter your home. TDG documents these findings and reports them to the relevant council or property owner for remediation.
Testing duration depends on the network size and complexity. A typical residential street section can be tested in 2-4 hours, including setup, smoke injection, defect identification, and documentation. Larger areas or complex networks require proportionally more time. TDG provides estimated timeframes during project planning based on the specific scope.
Properties in the testing area receive advance notification explaining the process and timeline. Residents should ensure toilet bowl water traps are filled (pour water down infrequently used toilets and drains), as dry traps can allow smoke to enter properties. There’s no need to vacate properties, but residents should be aware that smoke may emerge from drains or vents if connections are faulty.
TDG provides comprehensive reports documenting all identified defects with photographs, locations, and descriptions. Councils or asset owners use this information to prioritise remediation works, issue compliance notices for illegal connections, and plan capital improvements. TDG can also provide follow-up services including CCTV inspections, pipe cleaning, and rehabilitation to address identified issues.
Many North Island councils require smoke testing as part of infrastructure investigations, consent conditions, or network maintenance programmes. Smoke testing provides evidence of illegal connections and infiltration issues that councils must address under Resource Management Act 1991 obligations. TDG works closely with councils to deliver testing that meets specific requirements and compliance standards.
Testing frequency depends on network age, condition, and local council requirements. Many councils conduct periodic smoke testing every 5-10 years as part of proactive network management. Testing is also undertaken when investigating specific problems like unexplained flow increases, capacity issues, or before accepting new infrastructure. TDG can recommend appropriate testing intervals based on your network characteristics.
TDG Environmental’s hydro excavation services operate throughout New Zealand’s North Island, providing safe non-destructive digging solutions to urban and rural communities.
Auckland: Central Auckland, North Shore, Waitākere, Manukau, Papakura, Franklin, Rodney, Hibiscus Coast, Pukekohe
Waikato: Hamilton, Cambridge, Te Awamutu, Matamata, Tokoroa, Taupō, Thames-Coromandel, Hauraki, Waikato District
Bay of Plenty: Tauranga, Rotorua, Whakatāne, Kawerau, Western Bay of Plenty, Ōpōtiki
Hawke’s Bay: Napier, Hastings, Wairoa, Central Hawke’s Bay
Taranaki: New Plymouth, Stratford, South Taranaki, Inglewood, Waitara
Manawatū-Whanganui: Palmerston North, Whanganui, Tararua, Horowhenua, Manawatū, Rangitīkei, Ruapehu
Wellington: Wellington City, Lower Hutt, Upper Hutt, Porirua, Kāpiti Coast, Wairarapa, Masterton, Carterton, South Wairarapa
Our strategically positioned fleet and experienced regional teams ensure rapid response times and consistent service quality across all North Island locations.
The TDG team is on call when you need immediate support. Get in touch.
TDG Environmental is the most experienced provider of sustainable waste and stormwater management solutions throughout New Zealand and Australia specialising in a comprehensive range of environmental services including:
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Australia 1300 330 294
NZ 0800 249 376 
info@tdgenvironmental.com 
