Water Damage Studies

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Plumbing Supply System Failure Risks
Plumbing Drain System Failure Risks
Toilet Failure Risks
Water Heater Failure Risks
Washing Machine Failure Risks

IBHS conducted a study of closed water damage insurance claims and used that information to identify the leading causes of water damage and develop solutions.

Plumbing Supply System Failure Risks

There are two common types of plumbing supply system failures. The first involves frozen pipes, which can burst due to a buildup in water pressure caused by freezing water in an adjacent section of pipe. These accounted for 18% of all plumbing supply system claims in the study. The second and most common type of failure occurs when the supply system material fails and results in a leaking or bursting pipe. This type of failure represents two of every three plumbing supply system claims in this study.

A review of homeowner’s insurance claims resulting from plumbing supply system failures from multiple insurance companies around the country revealed:

  • Plumbing supply system failures are the leading source of residential water losses, with 48% greater losses (in terms of total payouts) than the second leading source.
  • Plumbing supply system failures cost an average of $5,092 per incident after the deductible was paid.
  • Of the claims analyzed, 65% were caused by a failure of the plumbing supply system material, while 18% were caused by frozen pipes.
  • Frozen pipe-related failures resulted in losses that were roughly twice as severe as those caused by plumbing supply system material failures.
  • The risk of a frozen pipe failure is dependent upon the geographic location of the home, the location of the pipe within the structure, and the time of year.
  • Homes located in North Region states with plumbing in the basement and/or exterior walls have the greatest risk of a frozen pipe failure.
  • Plumbing supply lines to the exterior hose bib are the areas most vulnerable to bursting during freezing weather. In this sample, January was the month when pipes were most prone to freezing.
  • In this sample, homes that were 16 to 40 years of age represented a larger proportion of supply system material failure claims than their proportion of total policies.
  • The proportion of total water loss claims attributed to supply system material failure was twice as high in the South Region than in the North Region.
  • Of the claims analyzed, 22% of all supply system material failures occurred beneath the slab of homes without basements.

Plumbing Drain System Failure Risks

Most drain system failures occur when the sewer drain backs up and overflows into the home or as a result of material performance issues (such as when the drain system piping corrodes and leaks or a connection loosens). In IBHS’ closed claims study, 52% of drain system failures were caused by sewer backups, while 37% were related to material performance issues.

A review of homeowner’s insurance claims resulting from failed plumbing drain systems that occurred throughout the United States revealed that:

  • Drain system failures are one of the top five sources of residential water losses.
  • The average cost of a drain system failure was approximately $4,400 per incident after the deductible was paid.
  • The average drain system failure was 61% more costly in South Region states ($6,143 vs. $3,812) than in North Region states.
  • Drain system claims related to material performance issues increase steadily until the home reaches 40 years of age beyond which no clear trend emerges.
  • 68% of all drain system sewer backup claims occurred for backups in basements and nearly all of these were located in North Region states.
  • Sewer backup claims occurring for backups in basements were 23% more severe when the basement was finished compared to when the basement was partially finished and 65% more severe than in unfinished basements.
  • The Clean Water Act introduced in the 1970s by the Environmental Protection Agency included new laws that prohibited storm water drains from being connected to the sanitary sewer. The data in this study suggest homes in the North Region built after this prohibition experienced 30% fewer basement drain system sewer backups while homes built in the south region experienced a 68% reduction.

Toilet Failure Risks

Toilet failures are the second leading source of residential water losses, after plumbing supply line failures. Toilet backups/overflows may be due to faulty fill valves or clogged drain lines.

A review by the IBHS of homeowners’ insurance claims resulting from toilet failures submitted by multiple insurance companies around the country revealed:

  • 78% of all toilet failures were caused by faulty supply lines, toilet flanges, fill valve assemblies or toilets that have backed up and overflowed.
  • Toilet failures cost an average of $5,584 per incident, after the deductible was paid.
  • Slow leaks resulting from faulty drain lines and toilet flanges (wax seals) generally result in less severe claims than those caused by the sudden failures of supply lines, fill valves, overflows and a cracked tank or bowl.
  • Newer homes are more likely to have a water loss caused by a sudden failure, which results in more severe damage.
  • Older homes are more likely to experience a water loss due to a slow and seeping failure. The loss severity decreases as the home ages.
  • Toilet failures on the first floor resulted in more severe claims than those in basements or on upper floors.
  • Approximately 14% of all toilet failures occurred in unoccupied homes.

Water Heater Failure Risks

Most water heater failures occur when the water heater has reached its life expectancy and the tank begins to rust and corrode. This is true since the majority of water heater failures involve leaking or bursting, usually as the result of a deteriorated tank. Proper maintenance, including inspecting the water heater’s anode rod and flushing sediment from the tank, can delay the need to replace a water heater.

A review of homeowners’ insurance claims resulting from water heater failures from multiple insurance companies around the country revealed:

  • Water heater failures are one of the top five sources of residential water losses.
  • 69% of all water heater failures result from a slow leak or a sudden burst.
  • Water heater failures cost an average of $4,444 per incident after the deductible was paid.
  • Supply line failure was the cause in only 10% of claims, but these claims typically were 60% higher than those caused by leaking or bursting.
  • The age at which a water heater tank failed due to leaking or bursting was available for 32% of the claims. Water heaters up to 20 years old accounted for 95% of these claims.
  • Failures of water heaters located on the first floor resulted in 33% greater losses than those resulting from water heaters in basements.
  • Approximately 9% of all water heater failures occurred in unoccupied homes and resulted in 49% higher claims.

Washing Machine Failure Risks

Washing machine-related failures are one of the top 10 leading sources of residential water losses. The typical causes are supply hose failures, machine overflows and drain line failures. 

A multi-company and multi-region study of homeowners’ insurance claims from water damage caused by washing machines revealed:

  • These failures cost an average of $5,308 per incident after the deductible was paid.
  • Failures of supply hoses accounted for more than half of all washing machine-related losses.
  • Of the water supply hose failures resulting in water loss claims, 78% involved washing machines that were less than 11 years old. Of these failures, 54% occurred in washing machines between eight and 10 years of old.
  • The proportion of washing machine related claims to total water loss claims was 67% higher in South Region states than in North Region states.
  • The average claim severity for South Region states was 28% higher than North Region states.
  • Although the affect of washing machine location on claim frequency could not be determined in this study, in the North Region, claims for units located in basements were 24% higher than claims for units located on the first floor.
  • Approximately 6% of all washing machine failures occurred in unoccupied homes.
  • Failures that occurred in unoccupied homes resulted in claims that were on average nearly two-and-a-half times more severe than those occurring in occupied homes.

IBHS’ Recommendations for Reducing Washing Machine-Related Water Damage

If possible, install a washing machine on an upper floor or in the basement. Washing machine failures on the first floor of a home resulted in 28% greater losses due to the proximity to valuable furnishings and electronics.

The failure of a water supply hose is the primary cause of loss. Conduct monthly inspections of the hot and cold washing machine supply lines:

  • Look for signs that the supply hose may be ready to fail. These include blisters in the hose, worn tubing, stress cracks or a loose connection.
  • Replace the supply hose with a reinforced steel braided hose if it shows any sign of wear.
  • Tighten the connection if it feels loose. The most common site of failure is near the connection where the hose bends.
  • Replace supply hoses every five years, even if there is no obvious deterioration or wear. Some signs of deterioration may occur from the inside out and may not be visible until it is too late. When replacing washing machine supply hoses, always choose a reinforced steel braided hose over the traditional un-reinforced rubber hose. These hoses will last longer and are far less likely to result in a catastrophic water loss.

To further reduce the risk of failure, turn off the hot and cold water supply valves when the machine is not in use. Always turn off the valves if you will be away for several days.

Screw type valves can be difficult to operate and may develop leaks around the shaft. If a valve is not operating properly or is leaking, replace it immediately. A better solution – and one that will make shutting off the water supply easier – is to install a dual ball valve lever operated valve. This type of valve is easier to operate than a traditional gate valve since it turns on both the hot and cold water supply with a single lever.

Finally, follow the manufacturer’s instructions to reduce the risk of other types of washing machine related water losses. Never overload a machine, always use a detergent designed for this type of use and try to operate washing machines when someone is home.

For more information on common plumbing-related issues, visit the IBHS Plumbing Resource Center.