Managing Flooded Grain Bins

Agricultural Disaster Preparedness and Recovery, Floods October 02, 2013 Print Friendly and PDF

Managing Flooded Grain Bins

Grain bins exposed to floodwaters are likely to have sustained damage and some grain loss can be expected. It is, however, often possible to repair bins and salvage at least part of the grain.

Water does not "wick" very far in whole grain, so it is likely that grain above the water line is still in good condition. It might even be possible to salvage grain that was submerged in floodwaters, but quick action will be required to prevent spoilage of this very wet grain.

Actions necessary for salvaging flood-damaged grain depend on the extent of damage to both bin and grain, so the first step is to inspect the bin, including unloading and aeration equipment, and the stored grain. Then, contact your insurance company or disaster relief agency as soon as possible to find out what you need to do to document losses.

With only a few exceptions, flood-soaked grain is not useable for feed or food. Flooding affects both the stored grain and the storage structures.

Grain and Grain Products

Flood-damaged grain is adulterated grain because of the potential for many contaminants to enter through the water. This grain should be destroyed, never blended. Contact local public health and sanitation officials for the best disposal process in your area.

Water coming up from tiles and pits is just as suspect as overland water. Even field tile water may contain animal waste products, high chemical levels and other contaminants.

The moisture will not travel more than a few inches above the flood line. Good grain on top of flooded grain must be removed from the top or side, not down through the damaged grain. Remove grain that is in good condition before attempting to do anything with the portion damaged by floodwaters.

Toxins are likely in rewetted grain. Warm wet conditions are ideal for mold growth. Soaked grain will spoil within a day or two at high moisture and summer temperatures.

Rain damaged grain, which may occur when roofs of storage structures are damaged during storms, can be saved by drying and cleaning. This grain should be tested for mycotoxins before use. Use reconditioned grain immediately.

Take care not to track or mix mud or gravel from flooded grounds into good grain during salvage operations. These materials are potentially toxic for the same reasons as the floodwaters.

The U.S. Food and Drug Administration (FDA) allows for reconditioning (washing and drying at high temperatures) in cases where the floodwater did not remain long and did not contain contaminants. It is very rare to know for certain whether floodwater is clean, however.


Grains swell when wet so bin damage is likely. This is more likely to occur in stored soybeans than other grains. Bolts can shear or holes elongate. Look for signs such as stretched caulking seals, misaligned doors or similar structural problems.

Check bins with stirring devices carefully. The bin must be perfectly round for them to work correctly.

Bin foundations can shift, float or deteriorate from flooding. Inspect structures and foundations carefully, and have an engineering evaluation for larger bins.

Expect electric wiring, controls and fans to be ruined. Do not energize wet components. Be sure the power is off before touching any electrical components of flooded systems.

Wood structures may sustain more damage than metal structures and will also retain mold and contaminants.

Clean facilities and grounds completely.


In the rare situations where the water was not contaminated, the grain may be reconditioned. If the grain is to be sold, reconditioning must be done with the written consent of the FDA. For feed on site, producers have three alternatives:

  • Dry the grain
  • Feed it immediately to their livestock
  • Ensile the grain for livestock feed

Decisions need to be made quickly, because wet grain will spoil within a couple days at warm temperatures. The wet grain will likely plug bottom unloading equipment, so the grain will need to be removed from the top.

Uncontaminated soaked corn can be used as livestock feed if used within a day or two before spoilage occurs. Moldy grain should not be fed to livestock. Just replace the corn in the animals' current diet with the wet corn. Remember to adjust amounts fed for moisture.

Wet, whole soybeans can be fed to cattle if the soybeans are limited to 10 to 12 percent of the ration's dry matter. Soybeans substitute well for the protein in soybean meal, but they need to be fed with a vitamin-mineral-additive premix if substituted for a complete protein supplement.

It is not necessary to heat-treat the soybeans for cattle. Also, if adding whole soybeans to diets high in distillers' grains, watch the total ration fat content. For hogs, raw soybeans can only be fed to mature sows. The soybeans need to be heat-treated if fed to younger pigs.

Answers to some potential questions about flooded grain bins:

How much time does it take for wet grain to spoil?

The rate of spoilage for wet grain depends on its moisture content and temperature. Grain that was submerged for more than a few days will have a moisture content of about 30 to 50 percent. At warm spring and summer temperatures, grain this wet will become moldy in a few days.

If the bin was only partly submerged, can dry grain be left on top of the wet grain?

Dry grain will be relatively safe for a few weeks, but it would be best to separate it from the wet grain as soon as you can because the wet grain will begin to spoil in a few days and generate heat and odors that could reduce the quality of the dry grain above it. Try to unload the dry grain without mixing it with the wet. Using a vacuum-type grain conveyor to suck the dry grain out the top of the bin might be the best way to do this. Consider selling the dry grain, moving it to an undamaged storage bin at your place or a neighbor's place, or temporarily storing it in a machine shed or other building modified for grain storage.

What can be done with grain that was exposed to flood waters?

If the grain is not contaminated with excessive silt, bacteria, fuel, or chemicals, it might be possible for you or a neighbor to feed wet grain directly to livestock. Remember that wet grain will spoil quickly; if it cannot be fed in a few days, consider adding a grain preservative to extend shelf life. If the grain moisture is between 25 and 35 percent, consider ensiling it in an upright silo, plastic-covered horizontal silo, or plastic silage bag. Beware that grain in ruptured bins could contain bolts, bin hardware, or other debris that should be separated out (consider using grain cleaners and/or magnets) before the grain is fed.

Another option is to dry the wet grain in a gas-fired dryer. Be aware that after drying, grain should be cooled to less than 60 degrees Fahrenheit for safe storage.

If you can remove the dry grain from the top of the bin and get the fan going, you might be able to use unheated air to dry a very shallow layer of wet grain in bins equipped with full-perforated floors and large drying fans. Chances of success for unheated air drying decrease as grain moisture, outside temperature, and grain depth increase.

Under certain conditions, grain molds can produce mycotoxins that can cause animal feed refusal, health problems, or even death. Since beef cattle (except for breeding stock), are somewhat less sensitive to molds and mycotoxins than other animals, feeding suspect grain to beef cattle as part of a mixed ration would be safer than feeding to other animals. If grain develops a lot of visible mold, test for mycotoxins before feeding it or spending money to dry it. Grain that is badly damaged by mold or has high levels of mycotoxins should be discarded.

How should the bin be unloaded?

Grain probably cannot be removed through the bin's unloading system. If electric motors on the unloading system have been underwater, it is best not to start them until they have been cleaned, dried, and lubricated. Very wet grain probably will not flow out of the bottom-unloading sump anyway. Consider using a vacuum-type grain conveyor to suck the grain out of the top of the bin. If the water line was below the level of the side door on the bin, it might also be possible to insert an auger into the dry grain through a small opening in the side door. Make sure the auger extends to near the center of the bin, however, because unloading a bin from one side creates uneven sidewall pressures that can damage the bin.

What kind of bin damage is likely in flood situations?

It is not unusual to find structural damage to bins after floods. Because grain swells when it absorbs moisture, it exerts a great deal of pressure on the inside of bin walls, often resulting in stretched bolt holes, broken bolts, and torn bin sheets. Sometimes, bins are knocked off their foundations or dented by the pressure of moving water or by impacts from floating debris. Rapidly moving water can also cause erosion around foundations.

Drying, aeration, and unloading equipment on bins are likely to be inoperable immediately after floods. In many cases, however, electric motors and controls, and gas burners will work again after they are cleaned and dried. Mud in electrical motors and equipment may cause electrical faults and other damage. Do not try to start electric motors until they have been cleaned and dried or they might burn out. You should also clean mud and debris off of fan blades to prevent imbalances that might lead to bearing damage. In many cases, aeration ducts and areas under full-perforated floors will contain mud and saturated grain fines. Clean these areas before the bin is filled again.

Companies that work on grain bins are likely to be quite busy after widespread flooding, so if repair work is needed, try to line up a contractor as soon as possible to get bins repaired before next harvest.

Are problems likely if water surrounded the bin foundation, but did not actually flow into the grain?

If the bin has an elevated, full-perforated floor, and the water level remained below the floor, the grain is probably fine. You might still need to check for erosion around the foundation, damage to the fan and unloading system, and mud accumulation under the floor.

If grain rests directly on a concrete floor, it is possible that water moved up through small cracks and pores and wet a few inches of grain next to the floor. It is also possible that in-floor aeration ducts are full of water and mud and that the fan and unloading system have been damaged by water. If you can get the aeration system to work, attempt to dry the layer of wet grain by aerating it. Or, if you can get the unloading system to work, consider transferring grain from one bin to another to get the layer of wet grain off the floor before it molds.

Are there safety concerns about working around flooded bins?

Possible safety hazards include electrical short circuits, gas leaks, sudden rupture of weakened bins, entrapment in flowing grain, and breathing dust and mold spores from damaged grain. Turn off gas valves and electrical power until you have a chance to clean, dry, and inspect gas and electrical systems. Work in pairs and stay out of flowing grain. And finally, wear a tight-fitting, high-quality dust mask or respirator that is designed to filter mold spores and other toxic dusts when handling flood-damaged grain. The mask will generally have an N-95 rating and two straps.

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