8 ¼” bit for 5” casing should be good. That gives you about 1 ½” of space for gravel all the way around the casing. I don’t know about not using mud? Mud is what keeps the hole open until you get the casing and gravel down. You need a consistent layer or thickness of gravel all the way around the perforated casing. If you push perf casing into sand, you will always pump sand.
Air rotary rigs don’t usually drill very well when they encounter a water-bearing zone, because it caves in without mud to hold it open.
Silica sand comes in bags and can be sized to filter the particular size particles in the well. Smaller water-bearing sands need smaller gravel as a filter. And smaller gravel needs smaller slot size to keep the gravel out of the well. Skill saw perforations are very large, requiring large gravel, and then you get a sandy well.
The 20’ of rat hole to catch the sand is not a good idea.
Here is a link to some Silica sand I found.
http://www.targetproducts.com/UserContent/SpecSheets/fltwatwlAB.pdf
First off, your driller is not a well driller.
That will make a big difference when it come time to develop the well.
There is a lot more to a well than just digging a hole in the ground.
Drilling in large sand and gravel needs to be done with a mud rotary rig. Without mixing mud to hold the sand and gravel back, it is like trying to keep a hole open in a box of marbles.
((
This is to help me understand a little about what you have.
Why is the well you have 160' deep? Has it always pulled in air or is this a recent occurrence?
And why would the driller go 250' if there is water at 40 to 60 feet?))
If your well will be in sand or gravel, you would need to buy a screen that is sized for the sand where the water is going to come from.
The size of the screen can go from .006 and up to
? it just depends on the sand the well is being developed in. Most of ours around here are in the .010 to .014 range (that is in thousandths)
Unless you are trying to keep out small kids and animals, cutting them with a saw is never a good idea.
The casing you use should be (well casing) not just sch40 pipe. There is a difference.
Water well dude,
Thanks for the reply. Let me restate the situation.
The well driller is a person that regularly drills 250 foot deep, 8 inch boreholes for closed loop geothermal applications in our area. The geology here in central Oklahoma is that the bore holes will not quickly collapse. There is time to put in the vertical loop or, in the case of a water well, to place a PVC casing and then pour sand/gravel around the casing. I called him again tonight and sometimes he does use mud, but many (most) times he can drill the borehole without it.
The existing 160 foot well (40-50 years old) is recently (last summer) drawing air and due to the extreme drout, the water table is lowering. In the summer, when I irrigate around the house, the water looks "milky" indicating that the pump is cavitating due to the water table being unable to provide enough water to replenish the water being pumped out of the well. Last fall I had to replace the 1 HP pump, lower the pump placement by an additional 10 feet (to within 15 feet of the well bottom) and this winter the project is to put in a deeper well.
Yes, there is some water at 40-60 feet down, but the quantity of water is low and getting lower due to long term low rainfall. In this area, most all water well drillers now recommend putting in a 250 foot well as there are more water bearing gravels down lower. The geology is that there are water sands and then shale/clay layers and then more water sands with more and more available water the deeper you go.
I also understand that the casing should be 160 # PVC and I can get 5 inch diameter locally for about $2.50 a foot (20 foot lengths with bell ends). I can also get some sections of perforated 5 inch, 160 # PVC casing pipe and a woven "sock" to slide on the perforated casing to prevent sand intrusion into the casing (all from local pump water well supply house in Oklahoma City).
Many local drillers do not use perforated pipe, but cut it themselves in the PVC casing with a hacksaw blade so the cut is only about 20% around the casing diameter and many cuts being put in. The well drillers do not use a sock, but just washed gravel/stone outside the liner. The well supply house thinks this is "old school" and strongly prefer the pre made perforated pipe for the lower 40-80 feet and the use of the sock. Obviously, sections of the casing higher up are solid casing and not perforated.
The cost of the borehole digger is $ to dig a 250 foot deep 8 inch borehole. I would have the PVC casing on hand and he helps me put it in borehole, glue up the joints, fill the cavity space with sand/gravel and grout the upper twenty feet with cement. Well drillers that do all the above, are charging $20 or more a foot to drill and place PVC casing. Then the extra expense for electric submersible pump . . .
Once I have a PVC cased well, I can install a 1 HP submersible pump.
Does the above explain the situation?
Thanks for your help.
Steve
Excuse my ignorance but what are the differences between a geothermal hole driller and a well driller? Don't they use the same equipment?
Water wells need to be designed, constructed, and developed properly to make good, clean, drinking water. Geo wells are just a deep posthole with a geo loop thrown in and filled to the top with grout. People think $20 a foot is outrageous for digging a hole in the ground. But there is a lot more than deep postholes involved in making good water wells. The hole is just the first step in constructing a good well. There is some skill involved with drilling the hole, but real skill is needed to install the right casing, perforations, gravel, seal, and develop the well as needed.
Many a farmer has told me they have too many wells to hire out the work. So they purchase and old drilling rig and try it on their own. Then they start calling with the questions. How do I know how thick of mud to use, what kind of mud, how much volume, pressure, pull down force, rotation speed, what kind of bit, how do you keep the hole straight, how do you know when you are deep enough, do you wash out the mud, etc.? Why is my bit stuck in the ground, how do you get it out, how long can I wait to install the casing, what kind of casing, perfs, cap on bottom or not, what size gravel, surface seal, etc.? Then if they get that far the next questions are, how do you get the water cleaned up, how do you determine how much water you can get, what depth to set the pump, what is the best pump size, brand, shroud, splice, drop pipe, wire, controls, etc.?
The only reason I answer some of these questions is that I no longer make my living in the pump and drilling business. It would be crazy for a well driller who has spent years, untold thousands of dollars, and made all the mistakes possible learning these things the hard way, to just show you how to construct the perfect well. Many so-called professional well drillers still haven’t figured it out. There are no schools for this except the school of hard knocks.
I am not saying that paying $20 a foot means you have a driller that knows how to do these things properly. But at least charging you for a properly installed potable water well makes him obligated to make it right. If the customer isn’t happy he could lose his license. But if someone is only contracted to drill a hole in the ground, then a hole in the ground is what you will get.
If you're considering installing a water tank on your property, there are several important questions you should ask beforehand. Water tanks can be a major investment, so doing your research is critical before making this purchase. In this blog post, we'll explore the 12 most important questions to ask when shopping for a new water tank.
If you are looking for more details, kindly visit SINCO.
1. What material should the tank be made of?
The material of the water tank should be one of your first considerations, as it impacts durability, water quality, lifetime costs, and more. Common materials for water tanks include concrete, poly tanks, galvanized steel, stainless steel, and more. Concrete tanks are long-lasting but can be expensive. Plastic poly tanks are affordable but may need replacing sooner. Stainless steel offers superior durability for a higher price tag. Assess your budget, intended use, and longevity needs when deciding on a material.
2. What capacity tank do I need?
Carefully calculate what capacity tank makes sense for your intended purpose, family size, livestock needs, gardening plans, and other water uses. A tank that is too small may run out frequently or not meet your water demands. A tank too large is an unnecessary expense. Take note of periods of higher usage, such as summer months or during a vegetable garden's growing season. Allow for future expansion plans as well when deciding on a water tank's capacity.
3. How frequently will the tank need to be refilled?
Along with tank capacity, carefully consider how often you will likely need to refill the tank each year based on your water needs and habits. Will the tank be refilled by rainfall collection only or will you need to bring in supplemental water? What is your area’s average annual rainfall? How many drought periods typically occur? These are all factors that can impact optimal tank size and refill frequency.
4. What external construction considerations are needed?
External construction needs include a stable, reinforced base, level ground for installation, overhangs or secured lids to prevent contamination from above, and protection from sunlight exposure if your tank is plastic. You may need to construct a concrete, crushed stone, or compacted earth base for the tank. Also have electrical or pump lines installed if applicable. Address all of these prior to delivery of your tank.
5. How should internal tank components be configured?
Questions to consider about internal components include whether you want partitions or segments within the tank, what type of lining you need for potable water purposes, if interior ladders or lifts are included for access hatches, what cleaning access points are built in, whether baffles, weighted inlet pipes, or calming inlets should be installed to prevent interior erosion from incoming water flows, and compatibility with any existing plumbing infrastructure.
6. How will tank overflow be dealt with?
One very important consideration is planning for excess water outflow when your tank reaches capacity after heavy rains or frequent fills. Options for handling overflow include routing excess water to a secondary onsite holding pond, a rain garden, drainage areas away from structures, or even back into a graywater system for reuse around your property for non-potable water needs.
If you are looking for more details, kindly visit Water Well UPVC Filter Pipe.
7. How will water be extracted from my tank?
Assess extraction needs before purchasing a tank. Will you require an electric pump system or simply use gravity outlets? Do you need fittings compatible with particular plumbing fixtures, appliances, outdoor spigots or irrigation systems? Are backflow prevention devices needed? Clarify all water extraction components so your tank purchase or customization provides full functionality.
8. What kind of maintenance is required?
Factor in both short and long-term maintenance needs for your tank. This includes initial tank cleaning, periodic exterior surface cleaning and inspection, treatment to prevent algae or bacteria inside the tank, checking and replacing internal filtration systems or water treatment components, integrity testing for leaks, monitoring and repair of any cracks or problem areas over time, and verifying that pumps, electrical lines and extraction systems continue functioning.
9. What safety standards should my tank conform to?
Verify that any potential water tank meets protocols such as NSF/ANSI, UL, FM or other domestic and international quality and safety standards. Approved, inspected tanks ensure healthy, potable water for your purposes as well as structural stability and longevity. Research requirements for above or below ground tank installations in your geographic location as well.
10. How qualified is the vendor or installation company?
Only work with highly experienced water tank suppliers who provide you with detailed customer service, project consultation and transparent pricing. Check reviews, credentials, certifications and proven expertise in your particular type and size of water tank installation. Verify they follow regional protocols and can correctly handle permit processes. Ensure they will properly size, customize and install your tank suited for the exact specifications of your property.
11. Can existing rainwater harvesting systems be incorporated?
If you already utilize rainwater harvesting elements like gutters, downspouts, barrels or cisterns, determine whether your new water tank can be correctly integrated to take advantage of these. Divert guttering to channel precipitation directly into your tank, for example, or connect intermediate barrel storage to gravity feed into the main tank. Utilize preexisting rain catchment investments to offset water tank refill requirements where possible.
12. What are all included costs, options and long-term expenses?
The purchasing process should clarify total costs for the water tank itself plus required components like pumps, wiring, attachments and installation expenses. However, also project long-term costs for maintenance, cleaning treatments, filter or treatment system replacements, potential repairs, inspections and periodic pumping out of accumulated sediment if your tank lacks a bottom drain. Estimate total lifetime costs, not just initial purchase and setup fees, when determining your budget.
Choosing the ideal water tank entails careful consideration of all key factors - the 12 outlined in detail here are crucial questions to investigate before making this major investment. Addressing aspects from construction, capacity and maintenance to safety standards, vendor qualifications and expenses will ensure your tank purchase fulfills all intended purposes for years to come. With research and planning guided by these questions, you can have peace of mind knowing your tailored water tank system reliably meets your family's or property's specific water needs into the future.
If you want to learn more, please visit our website HDPE Dredging Pipes for Philippines.