Under the decision, the groundwater source is extracted from the lower Pleistocene aquifer (qp1). The maximum permitted extraction capacity is 45,000 cubic meters per day.

The location and scope of the sanitary protection zone for each well, measured from the wellhead, are defined as follows. In Van Mieu – Quoc Tu Giam Ward, the protection radii are 3 meters, 5 meters, 7 meters, 10 meters, and 20 meters. In O Cho Dua Ward, the protection radii are 10 meters, 15 meters, and 20 meters.

The Hanoi People's Committee assigned Hanoi Clean Water One Member Company, Ltd., to proactively coordinate with the Department of Agriculture and Environment, the People's Committees of O Cho Dua Ward and Van Mieu – Quoc Tu Giam Ward to determine boundary limits and install signage marking the sanitary protection zone at the site.

The company is responsible for installing, maintaining, and protecting signage for the sanitary protection zone of the groundwater extraction facility.

The company must also protect the water source it directly exploits and uses, and monitor and supervise all activities within the sanitary protection zone. If any act causing pollution or posing a risk of pollution is detected, or if activities threaten the safety of water extraction or violate water resource regulations within the protected area, the company must promptly prevent such acts and immediately report them to the nearest local authority for handling.

Discharging wastewater or disposing of waste into the sanitary protection zone is strictly prohibited. The discharge of untreated wastewater or wastewater that does not meet technical standards into the water source is also banned.

All activities within the sanitary protection zone must comply with regulations on water resource protection, environmental protection, and other relevant laws.

The People's Committees of O Cho Dua Ward and Van Mieu – Quoc Tu Giam Ward are responsible for coordinating the on-site identification of boundaries and the placement of sanitary protection signage for the Ngo Sy Lien Water Plant groundwater extraction facility.

The scope of the sanitary protection zone must be publicly announced on the wards' official websites and posted on local public notice boards.

Local authorities are required to implement measures to protect water quality in their areas, inspect and supervise activities within the sanitary protection zone, and receive and handle issues arising in connection with the protected area in accordance with their authority.