CLEANOUTS
It should come as no surprise that things that are located in the ground get dirty, and your home’s water well is no exception.
So we ask you, do you know when it’s time to have your water well professionally cleaned out?
How do you know if a well needs cleaning?
Here are some of the signs that could indicate a need to clean your well system.
- The well water is turbid, which means it is cloudy or has suspended matter in it.
- There has been a decrease in the well’s capacity—that is, the gallons of water per minute that the pump can supply to the system.
- The water has developed an odor or taste problem.
- The water tests positive for total coliform and/or overall biological activity. Work with a qualified water well system contractor to determine whether your well needs cleaning.
Why do wells need to be cleaned?
Bacteria. In the upper reaches of the well, and often extending deep into the water column due to pumping, the presence of oxygen encourages the growth of aerobic bacteria (bacteria requiring oxygen) and the oxidation of metals such as iron and manganese. Aerobic bacteria tend to cause clogging by the production of large amounts of slime and the entrapment of oxidized iron and manganese as well as other minerals such as calcite.
Debris from bacterial activity in the upper portions of the well tends to accumulate at the bottom of the well. Water in the lower portions of the well can become depleted of oxygen due to chemical reactions and bacterial activity, creating an environment for anaerobic bacteria (bacteria able to live without oxygen). These anaerobic bacteria, natural to the aquifer, are often responsible for methane gas, a fishy taste, various odors, and hydrogen sulfide (which causes a distinctive rotten egg odor). Aquifers, and therefore wells in them, may become anaerobic if hydrocarbons such as fuel oil or gasoline are spilled in them, and downgradient from uncontrolled trash deposits or manure piles. Such contaminant plumes will be preceded by increases in iron and manganese.
Many aquifers are naturally anaerobic, especially if hydrogen sulfide, methane, and carbon dioxide (derived from methane by bacteria) are present. Hydrogen sulfide and methane are common where there are oil and gas deposits, coal, and shale in the rock. Bacteria and other microbes known as archaeans generate hydrogen sulfide and methane as part of their metabolic processes. This kind of sulfide production is different from the process mentioned above. Microbes are versatile!
Sulfide corrodes steel and other metals and causes iron oxides and other minerals to deposit. Sulfide also combines with iron to form iron sulfides, which are hard and clog pores and fractures in rock, well screens, pumps, pipes and other equipment. Compounding these effects, sulfide oxidizing bacteria, which are aerobic, form spectacular light-colored slimes when they oxide the sulfide.
If nitrate is present in abundance, iron may also be oxidized (yes, without oxygen) and the iron oxides deposited. Often these processes occur together as the natural world works to reclaim your well.
Encrustation. This is the process by which a crust or coating is formed on the well intake and/or casing, typically through chemical or biological reactions. The cause may be chemical oxidation, such as that which usually forms calcite deposits, or it may be microbiological, as described. Such deposits may also trap fine sediment particles to form a weak “concrete.”
Fill-in: Over time, wells pumping from sand-containing aquifers may accumulate sediment in the bottom, closing off parts of a well screen or open borehole. Similarly, earthquakes or other vibration may cause parts of the well borehole to collapse, reducing capacity.
Sometimes there’ll be a blockage do to iron bacteria or a soft rock cave in. What we’ll do is is set up over the well and clean out any material that’s in the bottom. We can surge the well to clean. If the existing well doesn’t produce enough water to meet your needs, due to increased demand or reduced water table, we’ll deepen the well to get more water.
Chemical cleaning often involves the use of various acids to loosen or dissolve debris so that it can be pumped out of the well. Depending on the nature of the cleaning job, there are also polymers and “caustic” chemicals (that increase the alkalinity of the water) to remove debris. These chemicals may be used in combination or in sequence. Such chemicals must be selected to be safe to use in a potable water supply, and by a knowledgeable professional for safety and effectiveness.
Before proceeding to clean a residential (or any) well, a contractor will collect information and perform an inspection:
- Review of the well log or well record to determine depth and construction, perform a site review (access, etc.): Is it safe or effective to clean it?
- Pumping test and pump function test (the well problem may be the pump, not the well) evaluating performance
- The contractor may insist on a downhole video inspection to confirm well dimensions, look for obstructions, holes or other unrepairable damage, and try to confirm and pinpoint the location of the well clogging.
Such an inspection may lead to the conclusion that well cleaning is not cost-effective vs. constructing a new well.
The age of a well may determine which methods are used to clean it. If a well’s water intake areas or the well casing have corroded significantly over time, they may be damaged or destroyed by more aggressive cleaning practices. Long-entrenched deposits may resist the mechanical and chemical energy available, and a well’s design (for example slotted pipe intake) may cripple the effectiveness of a cleaning process. In such cases, a well owner may opt to proceed directly to new well construction or prepare for that option if cleaning is ineffective.
Well disinfection
Well cleaning should be followed immediately by a thorough disinfection of the well system and its immediate environment. Richards Resource Development – your Indiana Well Drilling Expert will perform this to ensure it is done correctly.
