How Deep Should a Well Pump Be? Depth Guide for Homeowners
Setting a well pump at the wrong depth is one of the fastest ways to burn out a motor. A pump set too shallow runs dry during drought; a pump set with insufficient clearance from the bottom intakes sediment and clogs. Here is what we found after reviewing well driller guidelines and manufacturer installation specs.
Quick answer: the standard depth rule
A submersible well pump should be set 10-20 feet below the lowest expected water level during the driest season, with at least 5-10 feet of clearance above the well bottom. The setting depth is not your static water level. It is your static level plus the expected drawdown when the pump runs hard, plus a safety margin. For most residential drilled wells in the eastern US, that works out to a pump setting of 50-150 feet, but your specific well log is the authoritative source.
Use this formula as a starting point: Pump setting = Static water level + Expected drawdown + 10-foot safety margin.
For context on what the full installation involves, including cost breakdowns by depth, see our well pump installation cost guide.
What factors determine the right pump setting depth?
Depth is not a single number. It is the result of four variables that interact with each other.
Static water level is how deep the water sits when nothing is running. You can measure this with a weighted string or tape. It is the baseline, but it is not enough information on its own.
Drawdown (dynamic water level) is how far the water level drops when the pump runs at full capacity. Sandy or fractured-rock aquifers with lower recharge rates can drop 20-50 feet under sustained pumping. Tight granite formations might only drop 5-10 feet. Your well driller often tests this during well completion. Check the well log for a yield test result expressed as GPM at a given drawdown.
Seasonal variation is what catches people off guard. A water table that sits at 60 feet in March may fall to 85 feet in late August after a dry summer. Design for the worst-case seasonal low, not the average. In many mid-Atlantic and southeastern states, seasonal drawdown of 10-30 additional feet is normal.
Pump GPM rating affects drawdown directly. A 10 GPM pump pulls water faster than a 5 GPM pump, dropping the water level more sharply. Brands like Grundfos, Franklin Electric, and Goulds rate their submersible pumps by GPM performance at specific depth settings. A pump rated for 10 GPM at 100 feet may only deliver 7 GPM at 200 feet due to increased head pressure. Matching pump GPM to your aquifer’s recharge rate matters for long-term depth planning.
For guidance on selecting the right pump GPM for your household, see our guide on sizing your pump for GPM requirements.
How to measure your well’s water level
Before setting a pump, you need to know two numbers: total well depth and static water level. Here is how to get them without specialized equipment.
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Get a weighted string or tape measure. Tie a small fishing weight or bolt to a string, or use a metal tape measure.
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Lower to the bottom. Drop the weight slowly until you feel it stop. Count the length of string down. This is your total well depth. Record it.
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Find the water surface. Dry the string and lower it again. Mark where the string transitions from dry to wet. That depth is your static water level.
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Calculate the available water column. Subtract the static water level from total depth. If your well is 200 feet deep and static level is at 80 feet, you have 120 feet of water column available.
For more accurate readings in deeper wells, electronic water level sensors are available from well supply retailers for $50-$150. These have a probe that signals when it touches water.
Your well driller typically records static water level on the well completion report. Most homeowners never consult this document, which is the most reliable source for depth planning. We recommend pulling the well log from your county health department before scheduling any pump work, since contractors who set depth without it are guessing at your drawdown, which often results in a pump set too shallow.
Setting the pump at the right depth
Once you have your static water level and drawdown estimate, the formula is straightforward.
Example: Static level is 80 feet. Your well log shows a yield test drawdown of 20 feet at 5 GPM. Add a 10-foot safety margin for dry seasons.
Pump setting = 80 + 20 + 10 = 110 feet
A few specifics that change the calculation:
- Minimum bottom clearance: Always maintain at least 5-10 feet between the pump intake and the well bottom. Sediment accumulates at the bottom of any well over time. A pump sitting too close will intake fine particles that damage the impellers. For gravel-packed wells, increase this clearance to 15 feet.
- Pitless adapter depth: The drop pipe from the pump connects to the pitless adapter, the sealed fitting that passes through the well casing below the frost line (typically 6-8 feet below grade). Pump setting depth is measured from the surface, accounting for this connection.
- Torque arrestor: Install a torque arrestor, a rubber device that centers the pump in the casing, to prevent the drop pipe from spinning against the casing wall during startup. Set one near the bottom and one at mid-depth for pumps set below 100 feet.
For the full installation process once depth is determined, see our step-by-step pump installation guide. If you are also wiring the new pump, our guide on wiring a submersible well pump covers the electrical requirements in detail.
What happens if the pump is set too shallow or too deep?
Set too shallow: the pump’s intake rises above the dynamic water level during heavy use or drought. The pump pulls air, loses prime, and spins dry. Most submersible motors have thermal overload protection, but it does not always trip fast enough. Motors have burned out in under a minute of dry running. Replacement cost for a burned-out submersible motor runs $300-$1,500 depending on the pump.
Family Handyman’s well system troubleshooting guide notes that “continuous pump operation without water flow suggests problems beyond DIY repair.” That is precisely what happens when a pump runs dry: it operates but delivers nothing, and the motor eventually fails.
Set too deep: not a direct pump problem, but every extra foot of setting depth adds drop pipe cost ($2-$5 per foot for materials) and makes future pump pulls more expensive. A pump set at 250 feet versus 200 feet adds $100-$250 in drop pipe plus extra labor for the longer pull. Set the pump only as deep as necessary.
Pump depth by well type
Not all wells work the same way, and installation depth varies by construction type.
Drilled wells (50-400 feet): the standard residential well in most of the US. Submersible pump is the right choice. Set 10-20 feet below seasonal low water level with 5-10 feet clearance from bottom.
Dug wells (10-30 feet): older, large-diameter wells dug by hand or excavator. These are almost always too shallow for a submersible pump. A jet pump with a foot valve is the typical solution. See our comparison of submersible vs jet pump installation for why well depth determines pump type.
Artesian wells: water is under natural pressure from the aquifer. The pump may be set shallower than a standard drilled well, sometimes only 20-40 feet below the wellhead. Consult your original driller records. Artesian conditions change the depth calculation significantly.
Gravel-packed wells: the driller places gravel around the well screen at the bottom. Increase bottom clearance to 15 feet minimum to avoid drawing gravel through the pump intake.
For guidance on selecting the right pump for your well type, see our page on choosing a submersible pump for your well.
FAQ
How do I find out how deep my well is?
Check your well completion report (well log), which was filed with your county health department when the well was drilled. It lists total depth, static water level, and yield test results. If you cannot locate it, measure the total depth yourself using a weighted string or rent an electronic depth meter.
Can I set my own pump depth without a well driller?
For wells under 150 feet, a homeowner with the right equipment (pipe wrenches, a pipe puller or tripod rig for deep settings, and a helper) can set a pump. For wells deeper than 150 feet, the drop pipe weight alone (roughly 0.34 pounds per foot for 1-inch polyethylene pipe) makes safe lifting difficult without a truck-mounted pipe puller. Most homeowners at that depth hire a well service company.
What happens if I set the pump too close to the bottom?
A pump set less than 5 feet from the bottom will intake sediment that accumulates there over time. Fine sand and silt particles wear down impeller vanes, reduce flow rates, and shorten pump life significantly. In extreme cases, sediment can pack tight enough to lock the impeller. Always maintain at least 5-10 feet of clearance, 15 feet in gravel-packed wells.
How do I know if my pump is running dry?
The clearest signs: water pressure at fixtures drops suddenly and the pump keeps running without building pressure. You may hear the motor running but get no flow at any faucet. If the pump has an above-ground pressure gauge, watch it. If it stays below 20 PSI while the pump runs, the pump is not moving water. Shut it off immediately and check your water level.
Does pump depth affect water pressure?
Depth affects the pump’s ability to deliver rated flow. Deeper settings mean more vertical head pressure the pump works against. A pump rated for 10 GPM at 100 feet will deliver less flow at 200 feet. However, household water pressure at the fixture is determined by the pressure switch settings (typically 30/50 PSI) and the pressure tank, not the pump depth. If pressure is low, check those components first before assuming the pump is too deep.