Authority works — CMDA
CMDA GPR Survey for Layouts, Termini and Metro Corridors
Corridor, layout and crossing surveys for projects in the Chennai Metropolitan Area, now planned to grow to about 5,904 sq km.
Quick AnswerA CMDA GPR survey maps the underground utilities under land or roads in the Chennai Metropolitan Area before a layout, terminus or corridor is built. Ground penetrating radar (GPR) picks up water trunks, sewers, power cables, fibre and pipelines. CMDA plans a region of about 1,189 sq km today, with expansion to around 5,904 sq km under way. For crossings, see details on HDD route survey.
What does CMDA do, and where does a survey come in?
The Chennai Metropolitan Development Authority plans the city region and approves layouts and large buildings, so a CMDA utility survey is the buried-services check behind a planning file or project. CMDA began as an ad hoc body in 1972 and became statutory in 1974 under the Tamil Nadu Town and Country Planning Act, 1971. It is chaired by the state's housing minister and based in Egmore.
Most city streets belong to the Greater Chennai Corporation and the suburban bodies. CMDA matters on larger schemes: wholesale markets, bus termini such as Kilambakkam and Madhavaram, and the Outer Ring Road corridor. Its master plans also steer where new roads and services go.
How far does CMDA's area reach in 2026?
Legally the Chennai Metropolitan Area still stands at about 1,189 sq km, with a planned expansion to roughly 5,904 sq km. Reports in October 2026 said the state had begun the steps to bring in parts of Chengalpattu, Kancheepuram and Tiruvallur districts and Arakkonam taluk in Ranipet district. CMDA has decided to cover the added areas in its Third Master Plan, which is still being prepared. Until the new boundary is notified, check which body handles your site. (Source: DT Next, 8 October 2026.)
Which CMDA-linked projects need a utility survey?
Projects that move large volumes of earth across land where trunk services already run. Typical cases are new layouts, termini and markets, Outer Ring Road links, trunk mains for growth areas and lake-edge works where outfalls cluster.
Long schemes are scanned as one band, so every crossing has a depth before design is fixed; read about utility corridor mapping for how the band is drawn.
Why is HDD so common on metropolitan corridors?
Water gets in the way. The Adyar and Cooum, the Kosasthalaiyar in the north, the Buckingham Canal along the coast and hundreds of lakes and tanks cross the region. Open-cutting across them is slow and needs extra clearances, so fibre, power and smaller pipes often go under by horizontal directional drilling.
Before drilling under the Cooum or a tank bund, both banks are scanned and services near the launch and reception pits get depths. The bore-profile drawing is described with the details on HDD route survey.
What ground will the radar meet?
Sandy coastal soil in the east, clay and silt along the rivers and drier, gravelly ground to the west. As a geophysical method, radar depends on the electromagnetic properties of whatever it passes through, and Chennai's soils vary sharply in that respect. High groundwater in coastal sand cuts penetration, and river clay limits it further. Towards the western industrial belts, drier soils let the radar see deeper, though stony fill on new plots scatters the reflected signals.
Each soil type gets its own antenna and line spacing, and hand-taped chamber depths check the radar. Radar waves behave differently in each district. City-specific notes are on GPR survey in Chennai details, and field stages are listed when you see the utility survey guide for Chennai.
CMDA work at a glance
| Part of the region | Typical project | Survey focus |
|---|---|---|
| City core | Large building, transport hub | Dense services at the plot edge |
| Southern suburbs | Layouts, link roads, terminus works | Water and power trunks, drains |
| Northern and western fringe | Industrial and township roads | Pipelines, HT cables, fibre |
| River and lake edges | Bridges, outfalls, bores | Bank-to-bank service depths |
Table note: streets within the city corporation's 200 wards are handled through Mezux Greater Chennai Corporation utility survey.
How does a survey help a layout or planning file?
It shows the designer early which buried lines limit the plan, so roads, plots and drains go around them. On a peri-urban site the issue is often one trunk main, gas line or HT cable that nobody marked on the sale deed. Finding it before the layout is drawn changes the plan cheaply, while finding it after approval can cost a revised file and months.
The hand-over gives one site plan of every service on your grid and a strip either side of each trunk line. A crossing list for internal roads and drains and chamber photos complete it.
Your architect or consultant writes the planning application. We supply proof of the buried constraints that CMDA reviewers or the line owner can test.
What does a CMDA utility survey cost?
₹24 per metre standard and ₹32 per metre for an L-section, with a ₹1,00,000 minimum per project and GST on top. Long metropolitan programmes see the whole order reduced: 25% past 100 km, 40% past 500 km and 50% past 1,000 km.
An L-section along 25 km of link road totals ₹8,00,000. A 110 km pipeline route at standard rate drops from a list figure of ₹26,40,000 to ₹19,80,000 after the 25% discount. A Mezux surveyor lives in Chennai and can reach any metropolitan site within hours of the order, inside one business day at most. Should mobilisation or travel be chargeable on a CMDA site, the quotation prices it separately.
How are terminus and layout sites tied to survey control?
Through a few DGPS stations on the site boundary, from which everything else is measured. CMDA layout approvals and termini rely on site plans drawn to coordinates, and buried trunks must sit on the same base. Our surveyors set DGPS survey stations around Chennai on the boundary, then record internal roads, drains and chamber covers with a total station site survey. Each trunk, sewer or HT cable found by radar is placed on that base with depth and level, ready for the planner's overlay.
Who carries out GPR survey on CMDA projects?
Our own staff. Mezux Touch was set up in 2003 and has never handed field work to outside crews. Its kit, 58 radar units plus 18 HDD rigs, is company property, and quality, environment and safety are audited to ISO 9001, 14001 and 45001. CMDA has placed work orders with us directly. Developers, contractors, planning consultants and utilities on construction projects also engage us, and their CMDA submissions carry our sheets. Southern suburbs are covered on our Tambaram Municipal Corporation utility survey for your site page.
For CMDA utility mapping on a layout plan or corridor alignment, get a written quote for Chennai from the Mezux team.
Frequently asked questions
Is CMDA the same as the Greater Chennai Corporation?
No. CMDA is the planning authority for the metropolitan region. The corporation runs the city's roads, drains and civic services.
Has the 5,904 sq km expansion taken effect?
Reports in October 2026 described the steps as under way (Source: DT Next, 8 October 2026). Until the new boundary is notified, confirm which body covers your site.
Do you cover the whole metropolitan area?
Yes. City and suburban sites alike appear on our page on survey coverage in Chennai, and every site gets the same GPR data format.
Can you provide ground levels for a layout as well?
Yes. A topographic survey for Chennai sites run with the scan gives your planner levels and utility maps together.
Can you survey a lake bund or river bank?
Yes, where access is safe. Banks are where outfalls, metallic pipes and old buried utilities often cluster.
Does a bore profile cost extra?
No. Bore profiles from a ground penetrating radar survey come within the per-metre scan rate, and anything beyond the standard set is itemised in the written quote.
Get a written quote for CMDA works
Chennai authorities
Written by Saniya Parveen · Technically reviewed by Rahul Rai · Updated 8 November 2026