Petrol pumps told to check E20 fuel for water contamination every 2-8 hours

State-run oil marketing companies (OMCs) have stepped up quality-control measures at petrol pumps across India, directing dealers to regularly inspect underground storage tanks and fuel dispensing nozzles for water contamination to protect the quality of ethanol-blended petrol (E20).

The instructions apply to more than 93,000 retail outlets operated by Indian Oil Corporation (IOC), Bharat Petroleum Corporation Ltd (BPCL) and Hindustan Petroleum Corporation Ltd (HPCL). Depending on the company, operating hours, shifts and prevailing weather conditions, dealers have been instructed to conduct checks at intervals ranging from two to eight hours.

The tighter monitoring follows concerns over the possibility of moisture entering fuel storage systems, particularly during periods of rainfall. Water contamination can affect the stability and quality of E20 petrol, which contains 20% ethanol blended with conventional petrol.

Different testing schedules at oil companies

The three state-run oil marketing companies have adopted different testing frequencies for their retail outlets. Most petrol pumps operated by IOC and HPCL are required to conduct checks every two to four hours.

BPCL, meanwhile, has revised its monitoring schedule, reducing the frequency of mandatory testing to once every eight hours. The company communicated the revised requirements to its dealers through a letter dated October 23, accompanied by an updated standard operating procedure (SOP) for ethanol-blended motor spirit, the industry's term for petrol.

Under the revised BPCL guidelines, outlets operating round the clock must conduct at least three water-contamination checks daily. Retail outlets operating for fewer than 24 hours are required to carry out at least two checks.

The first directive requiring more frequent water checks was issued in July, followed by another instruction in late October as several parts of the country experienced rainfall. The measures are intended to minimise the risk of water entering underground storage tanks and affecting the fuel supplied to consumers.

Water-finding paste used to detect contamination

The monitoring process relies on alcohol-resistant water-finding paste, which dealers have been instructed to use to identify water entering underground storage tanks.

The paste helps detect the presence of water at the bottom of storage tanks. However, the oil companies have not prescribed any particular brand or product for the exercise. Dealers are free to purchase suitable alcohol-resistant water-finding paste available in the market.

The increased frequency of testing is linked to the chemical properties of ethanol, which is hygroscopic, meaning it readily absorbs moisture from its surroundings.

When E20 petrol comes into contact with water, the ethanol can separate from the petrol and form a distinct water-ethanol layer at the bottom of the storage tank. This phenomenon is known as phase separation and can compromise the quality of the fuel being dispensed.

Dealers and oil companies share responsibility for fuel quality

The Marketing Discipline Guidelines (MDG) issued by the three state-run oil marketing companies place responsibility for preventing the sale of contaminated fuel on both the companies and retail dealers.

Under the guidelines, oil marketing companies must ensure that ethanol is blended with petrol in accordance with government-prescribed limits. Dealers, in turn, are responsible for ensuring that the fuel supplied to consumers meets the required quality standards.

According to government data, the three public sector oil marketing companies operated a combined 93,239 petrol pumps as of April 1, 2026. IOC accounted for the largest network, with 42,818 outlets, followed by BPCL with 25,323 and HPCL with 25,098. Private fuel retailers operated another 9,784 outlets.

Ethanol blending reaches 20% in India

The enhanced monitoring comes as India has significantly increased the proportion of ethanol blended with petrol under its ethanol-blended petrol programme.

According to the Petroleum Planning and Analysis Cell (PPAC), ethanol blending increased from 14.6% in the ethanol supply year 2023-24 to 19.2% in 2024-25. The blending level subsequently reached 20% between November 2025 and March 2026.

The government's ethanol-blending programme is aimed at reducing dependence on imported crude oil, strengthening domestic ethanol production and supporting agricultural incomes.

The expansion of E20 supplies has also increased the importance of maintaining appropriate storage and handling procedures across the country's fuel distribution network.

Fresh concerns over E20 quality and ethanol levels

The latest instructions on water-contamination checks come amid wider scrutiny of E20 petrol quality. On November 6, Karnataka's Food, Civil Supplies and Consumer Affairs Minister Rizwan Arshad said that four out of five petrol pumps surveyed in the state had supplied fuel with ethanol content exceeding the permitted 20% limit.

The Karnataka government had sent 63 fuel samples collected from seven districts to a certified laboratory. According to Arshad, some samples contained ethanol levels as high as 31.2%, including fuel sold by IOC, BPCL and HPCL. He also called for a compensation mechanism for vehicle owners and accountability for oil companies if blending limits were exceeded.

The three oil marketing companies disputed the findings, saying their own tests of 56 samples from Karnataka showed ethanol content between 19% and 20%. They questioned the state's sampling and testing procedures and sought access to the relevant laboratory reports, documentation and retained samples. The companies also proposed joint testing with state authorities.

Separately, the Ministry of Petroleum and Natural Gas said on November 7 that 893 E20 samples collected from depots and retail outlets across 27 states and Union Territories had met the prescribed ethanol-content specifications. The samples, tested by refinery and oil company quality-control laboratories, included 330 from IOC, 280 from BPCL and 283 from HPCL. All recorded ethanol content within the prescribed range of 19-21%.

In Karnataka, all 56 samples tested under the companies' quality-monitoring exercise also met the prescribed standards, recording ethanol content between 19% and 20%, with an average of 19.3%.

The ministry said the companies had raised concerns about the methodology used in the Karnataka government's October testing exercise and called for a transparent, jointly verifiable assessment to resolve the discrepancies.

Against this backdrop, the more frequent inspections of underground storage tanks and dispensing nozzles form part of the oil companies' efforts to strengthen quality control as the nationwide supply of ethanol-blended petrol expands.