Distribution Systems: A Best Practices Guide for Small Systems

Introduction

This guide is intended for owners and operators of all public water systems serving fewer than 10,000 persons.

This guide discusses the importance of maintaining your distribution system.

1. Distribution Systems

Distribution systems usually consist of:
Piping & Fittings
Pumps & Pump Stations
Meters
Storage Tank
Backflow Prevention Devices
Hydrants & Valves

2. Importance of Maintaining Your Distribution System

A properly maintained distribution system is important for ensuring that you can: provide high quality water to your customers, continue operating in the event of an emergency, help minimize property damage as a result of responding to an emergency, and help prevent contamination events. A properly maintained distribution system can also extend equipment life-cycles and minimize problems related to minor or major equipment failures.

3. Distribution System Routine and Preventative Maintenance Tasks

The following table provides suggested frequencies of routine and preventative maintenance tasks for systems under normal operation. However, any time a system experiences water quality issues, the appropriate tasks should be performed as frequently as needed. Contact your MassDEP regional office for more information.

Task:
Valve Exercising
Benefits:
* Improves reliability
* Familiarizes crews with valve location
* Identifies inoperable valves
* Locates obstructed valve boxes
* Ensures isolation of distribution system sections when necessary
Suggested Frequency:
Annually.

Task:
Flushing Pipelines
Benefits:
* Removes aged water from the pipeline
* Reduces buildup of biofilms and sediments
* Restores disinfectant residual
Suggested Frequency:
Annually for all piping.  More often in areas with water quality issues (e.g. dead ends).

Task:
Storage Tank Inspections
Benefits:
* Detects vandalism
* Identifies defects
* Ensures that access hatches are locked
* Ensures that vents, overflows, and drains are screened
Suggested Frequency:
Daily for vandalism. Quarterly for vent, hatches, overflow, etc. Annually for other items.

Task:
Storage Tank Maintenance
Benefits:
* Improves protection against sources of contamination
* Extends the useful life of the equipment
Suggested Frequency:
Every 3-5 years for cleaning
Painting and repairs as dictated by inspection

Task:
Routine Water Quality Monitoring (e.g., pH, temperature)
Benefits:
* Provides information on potential contamination of raw and finished water.
* Helps determine effectiveness of treatment.
* Helps assure the compatibility of the water with the materials.
Suggested Frequency:
Will vary depending on water quality and Massachusetts' regulations and policies

Task:
Inspecting and Flushing Hydrants and Valves
Benefits:
* Ensures that hydrants and valves are operable and that no water losses occur.
* Ensures that hydrants and valves are not susceptible to tampering
Suggested Frequency:
Once or twice per year

Task:
Maintaining Operating Pressure Range of Distribution System
Benefits:
* Reduces the risk of backflow contamination
* Helps your system provide better service to customers
* Reduces damage to infrastructure due to excess pressure
* Provides adequate fire flow
Suggested Frequency:
Continuously

Task:
Tracking Unaccounted for Water
Benefits:
* Can reduce pumping and treatment costs
* Helps identify leaks, breaks, stolen water, and inaccurate meters
Suggested Frequency:
Daily at the source
Monthly or during routine meter reading at customer connections

Task:
Testing for Presence of Excess Biofilms
Benefits:
* Indicates a presence of inadequate chlorine residual, possible high disinfection byproducts levels, and water stagnation
Suggested Frequency:
Monthly in conjunction with total coliform sampling

Task:
Monitoring Corrosion
Benefits:
* Identifies the need to modify treatment or conduct flushing
Suggested Frequency:
Annually

Task:
Checking for Normal Wear (such as in mechanical parts found in pumps and control valves)
Benefits:
* Can extend the useful life of infrastructure components
* Helps avoid unnecessary replacement or operational costs
Suggested Frequency:
According to the manufacturer's recommendation

4. Contact Information

For more capacity building guides or more information on how to develop the capacity of your drinking water system contact MassDEP Drinking Water Program as follows:

Website: http://www.mass.gov/dep/water/drinking/systems.htm#capacity

DWP email address: Program.Director-DWP@state.ma.us

Boston / Main Phone No.: 617-292-5770
Michael Maynard: 508-767-2735
Yvette DePeiza: 617-292-5857
WERO Contact: Mike McGrath at 413-755 - 2202
CERO Contact: Michael Maynard at 508-767-2735
NERO Contact: William Zahoruiko at 978-694 - 3232
SERO Contact: Michael Maynard at 508-767-2735

This guide is based on an EPA small system guide. For a copy of the EPA guide or other EPA information visit the EPA website at www.epa.gov/safewater/smallsys/ssinfo.htm.