# Ethanol-blended petrol: what changes at the pump

> What ethanol-blended petrol (E10, E12, E15, E20) means for a petrol pump under MDG 2024: the same 720–775 kg/m³ density range, the BIS standards, the special water-finding paste, and water-induced phase separation.

Canonical: https://dipdensity.watsinfo.com/guides/ethanol-blended-petrol-e20/
Last updated: 2026-11-02

**Short answer:** E10 and E20 are petrol with 10% and 20% ethanol. The density limits stay 720 to 775 kg/m³ at 15 °C. What changes is water: ethanol takes up water, so tanks and tank lorries must be checked with a water-finding paste suitable for ethanol-blended petrol, and any water treated at once.

## The blends

| Blend | Ethanol | Standard |
|---|---|---|
| E5, E10 | up to 5%, 10% | IS 2796 |
| E12, E15 | 12%, 15% | IS 17586 |
| E20 | 20% | IS 17021 |

## Density stays in the same band

MDG 2024's specification table gives **720 to 775 kg/m³ at 15 °C** for motor gasoline and for E10 to E20 alike. The daily density check, the ±3.0 kg/m³ comparison with the invoice, and [Table 53B](https://dipdensity.watsinfo.com/table-53b/) all work the same way.

## Water is the real change

Ethanol mixes with water. Petrol does not. If enough water gets into a tank of blended petrol, it pulls the ethanol out into a separate layer at the bottom. The petrol above is left weaker, and the bottom layer is unfit to sell.

That is why the MDG asks for a **water-finding paste suitable for ethanol-blended petrol** when checking tank lorry compartments (clause 1.2 vii). An ordinary paste may not show water that has taken up ethanol.

## What to do

- Keep dip pipe and fill caps tight, especially in the rains.
- Take the [water dip](https://dipdensity.watsinfo.com/guides/water-in-underground-tank/) every morning with the right paste.
- Report any water to your oil company at once (clause 1.4.1 b).

## Questions

### Do I use a different density table for E20?

The MDG gives the same density range for E10 to E20 as for plain petrol, and the density at 15 °C is found the same way, with Table 53B.

### Which standards cover the blends?

MDG 2024 Annexure 7 names IS 2796 for E5 and E10, IS 17586 for E12 and E15, and IS 17021 for E20.

## Sources

- [BPCL, Marketing Discipline Guidelines 2024](https://www.bharatpetroleum.in/images/files/MDG-2024-Effective-24-10-2024.pdf)