What is an oil soak pit used for in transformer installations?

An oil soak pit is part of spill control, usually a contained area that can capture oil released from a transformer, especially during rupture or draining. It helps prevent migration into soil or stormwater systems by providing a controlled volume with liner or impermeable base. Some designs use gravel and drainage paths to a sump or separator so water can be managed without releasing oil. It is common in substations, yards, and industrial sites with large oil filled equipment.