Article: Why Seasonal Homes Are at High Risk for Bacteria in Water

Seasonal homes (vacation cabins, lake houses, short-term rentals, and second homes) often sit unused for weeks or months at a time. While this can make them peaceful getaway spaces, it also creates ideal conditions for bacterial growth inside plumbing systems. Water sits still, temperatures fluctuate, and sediment settles, allowing bacteria to multiply in ways that don’t normally occur in actively used homes.

Understanding why seasonal homes are vulnerable helps you protect your water supply, prevent illness, and avoid expensive plumbing problems.

1. Stagnant Water Makes Bacteria Multiply Quickly

When water remains still for long periods, chlorine dissipates, oxygen levels drop, and temperature rises. These conditions accelerate growth of:

• Total coliform bacteria
• E. coli
• Pseudomonas and other biofilm-forming species
• Sulfur-reducing bacteria
• Iron bacteria

Stagnation also allows minerals and sediment to settle, which becomes nutrient material for microbial growth. Even municipal water becomes unsafe after extended stagnation.

2. Biofilm Builds Up in Abandoned Plumbing Lines

Biofilm is a slimy layer that clings to the inside of pipes, faucets, hot water heaters, fridge lines, and valves. Once it forms, it protects bacteria from disinfectants and allows harmful organisms to multiply.

Seasonal homes develop biofilm faster because:

• Water sits unmoving
• Temperature changes are greater
• Mineral-rich water settles inside plumbing
• Appliances go unused

When water is finally turned on, biofilm can break loose and enter drinking water, showerheads, and ice makers.

3. Well Water Risks Increase When Homes Are Vacant

Most seasonal homes rely on private wells. Wells require consistent monitoring and routine testing, but seasonal homes often go months without either.

Risk factors include:

• Flooding or runoff entering the well
• Damaged or loose well caps
• Pump disturbances
• Pressure tank stagnation
• Sediment buildup

When the home is unoccupied, contamination can spread unnoticed.

4. Water Heaters Become Bacterial Reservoirs

Water heaters in vacant homes often sit idle for months, allowing warm, stagnant water to reach ideal bacterial growth temperatures.

This increases the risk of:

• Legionella
• Pseudomonas
• General coliforms

Flushing the tank is critical before using the water.

5. Fridge Water Dispensers and Ice Makers Harbor Slime

Refrigerator lines are narrow, dark, and ideal for biofilm growth. If a seasonal home’s fridge water dispenser or ice maker sits unused, bacteria thrive.

Common problems include:

• Slimy film inside lines
• Dirty ice
• Mold inside the reservoir
• Sour or metallic tastes

These systems must be flushed thoroughly before use.

6. Seasonal Homes Often Have Old Plumbing

Vacation homes and cabins are frequently older structures with:

• Metal pipes
• Outdated fixtures
• Sediment buildup
• Corroded fittings

Old plumbing increases bacterial load and releases particles into water after periods of non-use.

7. How to Make Seasonal Home Water Safe Again

Before drinking or cooking with water, always do the following:

Flush the Plumbing System

Run all taps for 10–15 minutes, both hot and cold.

Flush and sanitize the water heater

Drain several gallons or fully flush the tank depending on condition.

Replace fridge filters and flush lines

Run several gallons through the dispenser.

Clean aerators and showerheads

Remove debris and soak in a sanitizing solution.

Test your water for bacteria

A simple at-home screening test can confirm whether:

• Coliform bacteria are present
• E. coli contamination exists
• Plumbing biofilm remains active

Testing should be done before drinking the water and again after the system has been flushed.

Seasonal homes are wonderful retreats — but their water systems require attention every time you return. Stagnant water, biofilm, well contamination, and old plumbing all increase bacterial risk. With proper flushing, cleaning, and quick at-home testing, you can confidently restore water safety and enjoy your home without worry.

By Ryan N., PhD