If you come home to a water spill, a leaky appliance, or have to deal with the aftermath of a flood, here is what you need to know to determine if your water damaged wood floor can be saved.

Water can cause damage in three different ways to a floor. You’ll want to pay attention to these areas to determine how much damage there is, and what can be done to fix or replace your wood floor.

The most common symptoms you may see in water damaged floors are surface or structural issues.

You may notice areas of discoloration in the wood, including dark or light patches, or finish that is blistering or peeling off the floorboards.

A simple spill or splash from a sink or water glass is not likely to damage your floors if it mopped up as soon as it is noticed. Many small spills are likely to evaporate before they cause significant damage.

However, large water leaks, floods due to storms, or slow leaks or drips that go unnoticed for a long period of time can cause damage. The longer the wood is exposed to elevated moisture, the higher the chance it will be damaged.

If you suspect or see a water leak, you should shut off the water to the appliance or the whole home as quickly as possible. You may have to call a plumber if you do not know where your water shut off valve is.

Your first goal should be to remove any visible water from your flooring either with towels or a dry mop, and then bring in fans or air movers to help dry things out further. You should call a flooring professional who can test the moisture content of your wood flooring to determine if water has soaked into the floorboards themselves. This is an important step if you had a major leak, or suspect a hidden leak that has gone on for an unknown amount of time.

If your flooring has been covered in water from a burst pipe, you will need to shut off the water supply as quickly as possible, or wait until the source of the water is stopped. The next thing is to remove the water from the floor. A wet/dry vacuum is a great tool to use in addition to a squeegee, mop & bucket, towels, etc.

You should remove and clean any other damaged materials like furniture, rugs, or drywall that has been exposed to water and put fans and air movers in the area to begin drying things out as much as possible.

Once the source of the water has stopped and the excess water is cleaned up, the floor will start drying immediately. How quickly the floor will dry back to normal depends on the conditions surrounding the floor, the type of flooring, and the extent of water damage.

Water always travels to the lowest spot it can. This means, even if you have removed excess or standing water from the top of your flooring, there may still be water that has seeped underneath your floorboards into your subfloor.

Water underneath your flooring does not dry out as quickly compared to surface moisture. All floors have a protective top coating that keeps water from immediately soaking into the boards, however, there usually is not this protective coating on the underneath or sides of the boards.

There are two main types of subfloors that flooring is installed over: concrete and wood.

Although in some cases concrete subfloors can be damaged by a severe flood, it is unlikely water will impact the structural integrity of a concrete slab.

Wooden subfloors, typically made from plywood, OSB, or other types of wooden boards, are likely to be affected whenever water soaks into them. If a leak or flood sits on your floor for 24 hours or more and/or reaches the edges of your floor and seeps underneath your flooring, it likely will need to be dried out completely. Usually, this will mean removing the flooring on-top of your subfloor.

If you see or suspect structural damage to your subfloor, it should always be replaced or repaired back to new condition. Signs may include loose flooring pieces or a floor that is undulating and uneven in areas. Wet or water-damaged subfloors that are structurally unstable can cause long-term problems with your home, and simply replacing the wood floor on top will not fix the problem. Loud squeaks and creaks are likely with an unstable subfloor.

You should have a flooring or restoration professional test the subfloor for moisture content to determine if it is possible to dry the floor out. Sometimes, subfloors can be dried out from below, either from a lower level or a crawlspace. But if the water damage was too significant and there is no easy way to allow airflow to dry out your subfloor, it should be replaced.

Many synthetic vinyl and composite wood-look flooring is advertised as 100% waterproof. What this means is that the boards are unlikely to swell or warp due to water damage (usually as long as it is dried up within 24 hours).

These floors are known to handle surface moisture and light water leaks well because as long as the water is dried up quickly, the floor is typically fine.

However, if water is left on the floor too long, or there is a flood across the entire floor, it is likely that water is seeped through the seams or around the edges of the floor and into the subfloor. In these cases, regardless if the boards themselves are waterproof, the floor must be removed and likely replaced, so the subfloor can be dried out and mold kept from growing.

An easy way to determine if there is water underneath your laminate or LVP plank floor is to dry the surface moisture with a towel and then step on different areas of the floor. If you see water coming up through the seams, or hear a squishing sound, you can know for sure that water is underneath your floor and it needs to be removed.

In summary, water damage is often the cause of many floor replacements. Wood floors can withstand light spills and leaks if they are dried up quickly, but even floors that are marketed as “waterproof” must usually be replaced when too much water sits for too long and seeps underneath into your subfloor.