drinking water
how the system works

To help you better understand how the VDE can provide our customers with potable water, and ensure its safety and long-term viability, here is a comprehensive slide show that explains how the system works.

The Drinking Water System

  • Source of Water
  • Treatment
  • Routine Water Testing
  • Storage
  • Distribution
  • Challenges & Progress
potable water system

From Our Wells to Your Faucet...

WaterFlow2

VDE Watershed

Water sources

Source Data:

                                    TYPE                GPM

WELL 1A/B/C:        Gravel-pack        130

WELL 2:                  Gravel-pack          70

WELL 5:                  Bedrock                35

WELL 6:                  Gravel-pack          75

TOTAL GPM (dependable yield): 310

TOTAL GPD (dependable yield): 446,400

PEAK DEMAND GPD: 300,000

*WELL 7A/B/C:        Gravel-pack      110gpm

*Glenwood wellsite: anticipated to be online by the end of 2026

meter house
Pump Control Building
variable frequency drives
Variable Frequency Drives

The water from all the wells is blended together at the Pump Control Building.

The variable frequency drives set the pumping rates.

Water Treatment

  • Greensand+ Filters
    • Iron Removal
    • Manganese Removal
  • Chlorination
  • pH Adjustment
filters1




How does a Greensand+ Filter work?

Routine Water Sampling

Monthly:

  • Bacteria at 4 locations in the distribution system


Quarterly:

  • Whatever NHDES requests, per a set sampling schedule
  • Recently: Nitrate, Nitrate, Uranium


Less Frequent, per sampling schedule:

  • Lead and Copper – annually
  • Asbestos, Arsenic, and Radon as required
Sampling1

Routine Water Sampling The Data

Sampling results from our lab and 4 system sampling sites:

 Parameter

  • Iron
  • Manganese
  • Chlorine
  • Bacteria

WQ Criteria

0.3 mg/L
0.05 mg/L
>0.2 mg/L
Absent

Data Range

0.00 – 0.10 mg/L
0.003 – 0.03 mg/L
0.5 – 1.1 mg/L
Absent

WQtestingStock

Storage Tank Capacity

  • Two concrete tanks: Snow Hill (200K gallons) & Hilltop (180K gallons
  • Water surface elevation in the tanks sets the pressure in the system

Two booster pump stations

SHboosterpumps
AP booster station

VDE's Water Distribution System

  • Approx. 50 miles of water main
  • Diameters vary from 8 inches to 2 inches
  • Materials include plastic, cast iron, and asbestos-cement
  • Some mains are very brittle
  • Flanges and saddles were attached using iron bolts
  • Limited isolation points
  • Two elevated zones that require booster pressure pumps
  • Rocks in the trench backfill cause numerous problems
  • System is 55+ years old, with limited historic investment

Service connections

Shut-off valve for house
In-line ball valve

Boosted Pressure Zones

The Snow Hill booster station re-pressurizes flow to pump water up toward Draper Mill Road.

The Link Lane station pumps water through the Anderson Pond Special Place off of the Hilltop tank.

Challenges

 

“Lost Water”

Losses from 2020-2025:

Water main leaks: 72.4 million gallons 

Service line leaks: 28.6 million gallons

It costs money to pump and treat every gallon of water, but we get zero revenue from water lost through leaks in the system.

Longwood Drive

Challenges

 

Brittle plastic pipes tend to crack lengthwise due to pressure from improper/poor backfill material.

Challenges

  • All gravel-pack wells accumulate screen precipitate of iron and manganese, which can enter the raw water flow into the treatment plant.
  • Frequency of filter cleaning, or backwashing, can impact finished water flow.
  • Flushing programs are in place, and used when we have the capacity.