East Bengaluru buyer answers

How do you check an apartment's STP and borewell compliance?

Direct answer: To check the STP in apartments you're considering, confirm whether the law requires one, then ask for the KSPCB Consent for Establishment and a current Consent for Operation, recent treated-water test reports and the plant's capacity. For borewells, ask for BWSSB or KGWA permission, summer yield and a water quality report.

Disclosure: acre&key’s advice is free to buyers.

Key takeaways

When it's required: 120+ units and 80+ KLD of sewage in sewered areas; 20+ units where there's no sewer line (Karnataka notification, 12 Mar 2024, as reported).
Two consents: KSPCB's Consent for Establishment (design) and Consent for Operation (running). Check the validity date.
Treated water has limits: in Bengaluru, BOD up to 20 mg/l and TSS under 50 mg/l under the 2017 national standard.
Size matters: in our example, 200 flats make about 86 KLD of sewage.
Our TEST check: threshold, evidence, treated water, source wells.

Our water questions guide covers where an apartment's water comes from. This page goes one step further: the papers and numbers that show the sewage plant and borewells are legal and working.

Does this building need an STP?

Karnataka's notification of 12 March 2024 split the rule by whether the area has sewer lines (The Hindu, news):

Area	In-situ STP required for
Served by sewer lines	120+ units and 80+ KLD of sewage
No sewer line yet	20+ units
Plants built before March 2024	Must keep running

Some newer areas on the city's edge don't have sewer lines yet, so even mid-sized projects there need a plant. Ask BWSSB or the local body whether this one does.

Which documents prove the STP is legal?

KSPCB approves an apartment STP in two stages, as Citizen Matters explains:

Consent for Establishment (CFE). KSPCB checks the design before the plant is built.
Consent for Operation (CFO). KSPCB checks the built plant before it runs. It's renewed periodically, so look at the validity date printed on it.

The same report notes a weak spot: the CFO is often issued before residents move in, when there's no sewage to test the plant with. So a CFO alone doesn't prove the plant works. Ask for test reports too.

What should treated water test at?

The national standard for STPs, notified on 13 October 2017 under the Environment (Protection) Rules, sets these limits:

Parameter	Bengaluru (metro)	Other areas
pH	6.5–9	6.5–9
BOD (mg/l)	Not more than 20	Not more than 30
TSS (mg/l)	Less than 50	Less than 100
Faecal coliform (MPN/100 ml)	Less than 1,000	Less than 1,000

Your plant's KSPCB consent may set its own conditions, so compare the reports against the consent too. A report that skips BOD or faecal coliform isn't telling you much.

Worked example 1: is the plant big enough?

Illustrative. A 200-flat complex, four people per flat, using 135 litres per person per day, with about 80% of supply becoming sewage. These are common planning assumptions, not a measured figure.

Step	Calculation	Result
Water use	200 × 4 × 135 litres	1,08,000 litres a day
Sewage (80%)	1,08,000 × 0.8	86,400 litres = 86.4 KLD
Plant rated at 60 KLD?	86.4 > 60	Undersized

An undersized plant runs overloaded, and you tend to smell it before you see it. Ask the facility manager for the plant's rated capacity and the daily inflow log, and compare.

Worked example 2: what reuse is worth

Illustrative. If that complex reuses 40,000 litres of treated water a day for flushing and gardens, and the alternative is tankers at ₹1,000 per 6,000-litre load:

40,000 ÷ 6,000 = 6.67 loads a day
6.67 × ₹1,000 × 30 = about ₹2,00,000 a month
Across 200 flats: about ₹1,000 per flat per month

The real saving depends on local tanker prices and whether the flats have dual plumbing for flushing. Ask the association for actual figures.

How do you check the borewells?

Permission. BWSSB began requiring prior approval for new borewells in its limits from 15 March 2024, under section 11 of the Karnataka Ground Water Act 2011 (New Indian Express, news). Registration and permissions run through the Karnataka Ground Water Authority portal.
Yield. Ask how many borewells still work in April and May, not how many were drilled.
Quality. Ask for a recent lab report tested against the BIS drinking-water standard, IS 10500, especially if borewell water reaches the taps.

The TEST check (our framework)

Threshold. Does the law require an STP for this size and area?
Evidence. CFE and a CFO that's still valid.
Treated water. Recent reports on BOD, TSS, pH and faecal coliform, within limits.
Source wells. Borewell permission, summer yield and a quality report.

Checklist before you buy

STP threshold checked for the area (sewer line or not)
KSPCB CFE and current CFO seen, with validity dates
Last three months of treated-water reports
Rated capacity compared with daily inflow
Treated water reused for flushing or gardens, with dual plumbing
Borewell permission or KGWA registration
Summer yield and a water quality report
STP operator contract and running cost in the maintenance budget

These sit alongside your site visit checks, the pre-token checklist and the occupancy certificate. For piped supply, see Cauvery Stage 5 coverage and our legal checks. Associations taking over a building can use our answers on handover and lift and DG documents.

Frequently asked questions

Is an STP mandatory for apartments in Bengaluru?

It depends on the area. Since March 2024, projects with 120 or more units and 80 KLD of sewage need an in-situ STP where sewer lines exist. Where there's no sewer line, the threshold is 20 units.

What is a KSPCB Consent for Operation?

It's the pollution control board's permission to run the STP after checking the built plant. It's renewed periodically, so check that the validity date hasn't passed.

What should STP treated water test at?

Under the 2017 national standard, Bengaluru STPs should discharge water with BOD up to 20 mg/l, TSS under 50 mg/l, pH between 6.5 and 9 and faecal coliform under 1,000 MPN per 100 ml.

How do I know if the STP is too small?

Estimate sewage: flats × people × daily use × 0.8. For 200 flats at four people and 135 litres each, that's about 86 KLD. Compare it with the plant's rated capacity.

Do apartment borewells need permission?

Yes. BWSSB has required prior approval for new borewells in its limits since 15 March 2024, under the Karnataka Ground Water Act 2011. The KGWA portal handles registration.

What is the TEST check?

It's our four-step STP and borewell check: confirm the legal threshold, see the consents, read treated-water test reports, and check the borewells' permission, yield and quality.

Talk it through with acre&key

If you'd like help reading an STP consent or a test report before you commit, we can go through it with you. Book a consultation with acre&key.

References

Checked 19 Oct 2026.

The Hindu, Karnataka makes in-situ STP mandatory for 120+ apartments in sewered areas, Mar 2024 (news): https://www.thehindu.com/news/cities/bangalore/water-woes-karnataka-amends-law-makes-in-situ-stp-mandatory-for-residential-complex-in-bengaluru-with-over-120-apartments/article67997490.ece
Citizen Matters, apartment STPs and the KSPCB CFE/CFO process: https://citizenmatters.in/bengaluru-apartment-sewage-treatment-plants-stp-kspcb-approval-cfe-cfo-reforms/
MoEFCC, Environment (Protection) Amendment Rules 2017, G.S.R. 1265(E), 13 Oct 2017 (copy): https://urbanemissions.info/wp-content/uploads/docs/India-Standards-Sewage-Treatment.pdf
New Indian Express, BWSSB borewell permission, 11 Mar 2024 (news): https://www.newindianexpress.com/cities/bengaluru/2024/Mar/11/water-crisis-legal-action-against-drilling-unauthorised-borewells-in-bengaluru-bwssb
Karnataka Ground Water Authority portal: https://www.kgwa.in/Public/home