How to Prevent Damage to Water Mains?

 Contents

  1. Introduction
  2. Precautionary Measures
  3. Avoid Malpractice
  4. Report Main Burst or Leak
  5. Contact Telephone Numbers

 

How to Prevent Damage to Water Mains

PDF version (687KB)

INTRODUCTION

Most of the bursts of underground water main are caused by road opening works directly or indirectly. To avoid inconvenience caused to the public, delay of works and liability for high repair costs, contractors should avoid malpractices and take all necessary precautions to protect water mains.

PRECAUTIONARY MEASURES

figure 1(1) Check Pipeline Alignment

Before works start, contractor should submit to the Water Supplies Department (WSD) layout plans indicating the extent of works so that existing pipeline alignment near the site can be marked on them. Contractor should check the returned drawings to see if any existing water mains may be affected.

PRECAUTIONARY MEASURES

figure 2(2) Use Pipe Detector

Before digging trial holes by hand, contractor should make use of pipe detector to ascertain the approximate alignment and depth of underground water mains.

PRECAUTIONARY MEASURES

figure 3(3) Hand-dug Trial Holes

Ascertain the exact position and depth of water mains by hand-dug trial holes, before using mechanical plants for road breaking and excavation.

PRECAUTIONARY MEASURES

figure 4(4) Careful Use of Plants

Be careful in operating heavy road breaking and excavation plants to avoid damaging water mains and valves near the work site.

PRECAUTIONARY MEASURES

figure 5(5) Protect and Support Pipes and Thrust Blocks

Provide adequate support and protection for all exposed water mains, thrust blocks and valves.

PRECAUTIONARY MEASURES

figure 6(6) WSD Assistance

You may consult the relevant Regional Inspector/(Inspection) of WSD for assistance in locating existing water mains and providing adequate cover and support for water mains.

PRECAUTIONARY MEASURES

figure 7(7) Backfilling

To prevent ground settlement adjacent to or below existing water mains, backfill the excavation with suitable materials in layers with adequate compaction.

PRECAUTIONARY MEASURES

figure 8(8) Site Supervision

Provide adequate site supervision to ensure that all necessary precautionary measures are taken, and remind workers and staff regularly of the importance of avoiding damage to water mains and the full implications of the damage.

AVOID MALPRACTICE

figure 9(9) Avoid Excessive Loading on Pipes

DO NOT pass heavy plants over buried water mains when the cover has been reduced by road opening works. This is to prevent possible damage to pipe due to excessive loading.

AVOID MALPRACTICE

figure 10(10) Avoid Disturbing Thrust Blocks

DO NOT disturb or expose thrust blocks without WSD's agreement.

AVOID MALPRACTICE

figure 11(11) Do Not Undermine Water Mains

DO NOT undermine water mains when excavating trench alongside or across them to prevent settlement of supporting ground.

AVOID MALPRACTICE

figure 12(12) Do Not Obstruct Valve and Hydrant Operation

DO NOT stockpile excavated material above valves or adjacent to hydrants to ensure that they can be accessed and operated at all times.

REPORT MAIN BURST OR LEAK IMMEDIATELY

figure 13(13) Report Main Burst or Leak Immediately

In case of water main burst or leak, please report to WSD immediately. Our emergency team will attend the incident immediately.

2824 5000
(Customer Telephone Enquiry Centre 24-hours Hotline)

CONTACT TELEPHONE NUMBERS

Contact telephone numbers of WSD's Regional Inspector/(Inspection) during office hours are as follows :

Region Contact Tel. No.
Hong Kong & Outlying Islands 2880 2536
Kowloon Region 2360 6544
New Territories West Region 2399 4347
New Territories East Region 2152 5755