Water Damage Restoration Glossary

Restoration crews and insurance adjusters use a lot of jargon. This glossary explains the terms in plain words and links each one to the page that covers it best. You can also browse our water damage guides or read about water damage restoration in Laurel.

• A
• B
• C
• D
• E
• F
• G
• H
• I
• L
• M
• N
• O
• P
• R
• S
• T
• W

A

Air mover

A high-speed fan that blows air across wet floors, walls and carpet so moisture evaporates faster. Air movers work together with dehumidifiers during structural drying. See water mitigation and structural drying.

Air scrubber

A portable machine that pulls room air through a HEPA filter to catch mold spores, soot and dust during cleanup. See mold remediation.

Antimicrobial

A cleaning product that kills or slows the growth of bacteria and mold on surfaces. It is used after sewage and flood water is removed. See sewage cleanup.

B

Backflow valve

A one-way valve on a sewer line that lets waste water leave the house but stops sewage from flowing back in during a backup. Read the sewage backup guide.

Black water

Another name for Category 3 water: grossly contaminated water such as sewage or river flood water. It can carry bacteria and viruses. See sewage cleanup.

Board-up

Covering broken windows, doors or wall openings with plywood after a fire or storm to keep out weather and intruders. See fire and smoke damage restoration.

C

Category 1 water

Clean water from a sanitary source, such as a broken supply line or an overflowing sink with no contaminants. It can worsen to Category 2 if it sits. See emergency water removal.

Category 2 water

Gray water with some contamination, such as washing machine or dishwasher discharge or a toilet overflow with urine but no feces. See emergency water removal.

Category 3 water

Grossly contaminated water, including sewage, toilet backflow from beyond the trap, and rising flood water from rivers or streams. Porous materials it soaks usually have to be removed. Read what Category 3 water means.

Class of water loss

A rating from Class 1 to Class 4 that describes how much water soaked into a room and how hard the materials are to dry. Class 4 covers dense materials like hardwood, plaster and concrete. See structural drying.

Containment

Plastic sheeting and zip doors that seal off a work area so mold spores, dust or soot do not spread to clean rooms. See mold remediation.

Contents pack-out

Boxing up and moving furniture and belongings out of a damaged home so they can be cleaned, dried and stored while work goes on. See fire and smoke damage restoration.

Crawl space

A short, unfinished space under a house between the ground and the first floor. Crawl spaces often hold pipes and ducts and can trap moisture. Read the crawl space mold guide.

D

Dehumidifier

A machine that pulls water vapor out of the air. Restoration crews use large low-grain refrigerant (LGR) or desiccant dehumidifiers to dry buildings. See structural drying.

Desiccant dehumidifier

A dehumidifier that uses a moisture-absorbing material instead of cold coils. It works well in cold basements and for very dense materials. See structural drying.

Drying log

A daily record of moisture readings, humidity and equipment used on a water damage job. Insurers often ask for it. Read mitigation vs. restoration.

E

Efflorescence

White, chalky salt deposits left on concrete or brick when water moves through it and evaporates. It is a sign of ongoing moisture in a basement wall. Read the flooded basement guide.

F

Flood stage

The water level at a river gauge where the river starts to cause flooding nearby. The National Weather Service sets flood stage for each gauge. Read the flood prep guide.

Flood zone

An area shown on a FEMA flood map with a certain level of flood risk. Homes in a high-risk zone with a federally backed mortgage usually must carry flood insurance. Read the flood prep guide.

French drain

A gravel-filled trench with a perforated pipe that carries ground water away from a foundation or to a sump pit. Read the sump pump guide.

Frozen pipe

A water pipe where ice has formed and blocked flow. Pressure builds between the ice and the faucet and can split the pipe. Read the frozen pipes guide.

G

Gray water

Another name for Category 2 water: water with some contamination that could make people sick if swallowed. See emergency water removal.

H

HEPA filter

A high-efficiency particulate air filter that traps at least 99.97 percent of particles 0.3 microns in size. Used in air scrubbers and vacuums during mold and soot cleanup. See mold remediation.

Hydrostatic pressure

The push of ground water against basement walls and floors. When soil is soaked, this pressure forces water through cracks and joints. Read the flooded basement guide.

I

Ice dam

A ridge of ice at a roof edge that traps melting snow. The water backs up under shingles and can leak into ceilings and walls. Read the ice dams guide.

L

Low-grain refrigerant dehumidifier

Often called an LGR, this dehumidifier cools air below its dew point to pull out water. It can reach lower humidity than a household unit. See structural drying.

M

Moisture map

A sketch of a room showing where moisture readings are high. It guides where to remove materials and place drying equipment. See structural drying.

Moisture meter

A tool that measures water inside drywall, wood or concrete. Pin meters read at a point; pinless meters scan below the surface. See structural drying.

Mold remediation

The process of containing, removing and cleaning mold growth and fixing the moisture that caused it. Killing mold is not enough; it must be removed. See mold remediation.

Mycotoxin

A natural chemical that some molds can produce. Health agencies advise removing indoor mold rather than testing for specific toxins. Read the mold growth guide.

N

National Flood Insurance Program

The federal flood insurance program run by FEMA, often called the NFIP. Policies usually have a 30-day waiting period before coverage starts. Read the Maryland insurance guide.

Negative air pressure

Setting up an air scrubber to exhaust more air than flows in, so air leaks into the work area instead of out of it. This keeps spores from escaping. See mold remediation.

O

Odor counteractant

A product that breaks down odor molecules from smoke or sewage instead of covering them with a scent. See fire and smoke damage restoration.

P

Pre-loss condition

The state a property was in before the damage. Insurance claims and restoration work aim to return the home to this condition. Read the insurance guide.

Psychrometry

The science of air, temperature and moisture. Drying technicians use it to set dehumidifiers and air movers for the fastest safe drying. See structural drying.

R

Relative humidity

How much water vapor the air holds compared with the most it could hold at that temperature, shown as a percent. Indoors, 30 to 50 percent is the usual target. Read about musty basements.

S

Sanitary sewer overflow

A release of untreated sewage from a public sewer pipe, often during heavy rain when storm water leaks into old pipes. Read the sewage backup guide.

Secondary damage

Damage that shows up after the first event, such as mold, swelling wood, peeling paint or rust, because materials stayed wet too long. Read mitigation vs. restoration.

Sewer lateral

The private pipe that carries waste water from a house to the public sewer main. The owner is usually responsible for most of it. See sewage cleanup.

Smoke residue

The film left by smoke on walls, ceilings and belongings. Dry, wet, protein and fuel-oil residues each need a different cleaning method. See fire and smoke damage restoration.

Soot

Fine black carbon particles from incomplete burning. Soot is acidic and can stain and etch surfaces if it is not cleaned soon. See fire and smoke damage restoration.

Standing water

Water pooled on a floor or surface. It should be extracted before drying begins, because fans alone cannot remove it. See emergency water removal.

Structural drying

Drying the building itself, including subfloors, framing, drywall and concrete, with dehumidifiers, air movers and monitoring, not just the surfaces you can see. See structural drying.

Subfloor

The plywood or board layer under finished flooring. Water that seeps through carpet or wood can soak the subfloor and stay hidden. See structural drying.

Submersible pump

An electric pump that sits in standing water and pushes it out through a hose. It is used first when water is several inches deep. See emergency water removal.

Sump pump

A pump in a pit at the lowest point of a basement that pushes ground water out and away from the house. Read the sump pump guide.

T

T&P valve

The temperature and pressure relief valve on a water heater. It opens to release water if the tank gets too hot or pressure gets too high. Read the water heater guide.

Thermal imaging camera

A camera that shows temperature differences. Wet areas are often cooler, so it helps find hidden water behind walls and ceilings. Readings are confirmed with a moisture meter. See ceiling and drywall water damage repair.

Truck-mounted extractor

A powerful vacuum system built into a service vehicle, with hoses run into the home. It pulls large amounts of water from carpet and floors. See emergency water removal.

W

Wall cavity drying

Pushing dry air into the space inside a wall or ceiling through small holes so it can dry without tearing out the whole surface. See ceiling and drywall water damage repair.

Water mitigation

The first, urgent stage after a leak or flood: stopping the water, removing it and drying the building to prevent more damage. See water mitigation.

Water/sewer backup endorsement

An add-on to a homeowners policy that covers damage from water or sewage backing up through drains or overflowing a sump pump. Maryland insurers must offer it. Read the sewer backup insurance guide.

Weighted extraction

Using a heavy roller or stand-on tool to squeeze water out of carpet and pad so it can be extracted, instead of only vacuuming the surface. See emergency water removal.

Wicking

Water climbing up drywall, wood or fabric from a wet floor, the way a paper towel soaks up a spill. Drywall can wick water well above the visible line. See ceiling and drywall water damage repair.