When an existing well can no longer keep up, two big options come up: drill the existing well deeper, or drill a new well somewhere else on the property. Neither is automatically better. The choice depends on why the well is failing, the condition of what you already have, and what the ground below offers.
Why is the existing well failing?
Deepening helps when the problem is that the water level has fallen below a shallow well, or that the well needs more storage in the hole. It does not fix a cracked casing, a poor surface seal, or water-quality problems from the formations already being tapped. Find out which problem you have; see signs your well is running dry and low-yield well options, where storage and rehabilitation may solve the problem without new drilling.
When does it make sense to deepen an existing well?
- The casing, seal and wellhead are in good condition.
- Water levels in the area have dropped, but deeper zones are known to produce.
- More borehole storage would bridge the gap to peak demand.
Penn State Extension notes that deepening an existing 6-inch well by 100 feet increases water storage by about 147 gallons, and that deepening can be a better option where water levels drop significantly in dry periods. Penn State Extension: Using Low-Yielding Wells [PSU-LOWYIELD source note]
What are the risks of deepening a well?
- Yield is not guaranteed. Deepening may not increase yield. Penn State Extension: Managing Your Well During Drought
- Quality can change. There can be significant changes in water quality as you deepen an existing well. Penn State Extension: Using Low-Yielding Wells
- Complications inside the well. Casing breaks or debris stuck in the well can complicate work on an existing well. NGWA (Wellowner.org): Restoring Flow through Water Well Rehabilitation
When should you replace a water well instead?
Penn State Extension says total well replacement may in the long run be more economical than rehabilitating a severely deteriorated well, especially a shallow well. Penn State Extension: Water Well Maintenance and Rehabilitation Replacement also lets you correct problems with the old well's location, such as being too close to a septic system or in a low spot that floods. [PSU-REHAB source note]
| Factor | Points toward deepening | Points toward replacement |
|---|---|---|
| Casing and seal | Sound | Cracked, corroded or unsealed |
| Well type | Drilled, adequate diameter | Dug, driven or very shallow |
| Problem | Falling water level, need for storage | Contamination, structural failure |
| Location | Meets current setbacks | Too close to hazards, floods |
| Past repairs | None or successful | Rehabilitation has failed |
Cost of drilling a well deeper vs. a new well
Deepening is usually priced per foot of new hole, plus the cost of pulling and resetting the pump and any new casing or liner. A replacement well carries the full cost of a new well: mobilization, drilling, casing, sealing, development, testing, a new connection to the house, plus decommissioning the old well. On the other hand, a replacement can be located better and built to current standards. Put both options into the well drilling cost calculator using each contractor's per-foot rate and maximum depth, then compare the high scenarios. If either option might fail to find water, read who pays for a dry hole before signing.
What should you ask before you redrill a well?
- What condition is the casing in, and how did you check?
- What do nearby well reports show below the current depth?
- What yield and quality changes are realistic?
- What would deepening cost per foot, and what is the maximum depth you would recommend?
- If replacing, where would the new well go, and who decommissions the old one?
Price both options with the well drilling cost calculator. Any old well you replace must be decommissioned; NGWA's owner checklist says to have a qualified contractor do this after the new system is built. NGWA (Wellowner.org): Homeowner's Maintenance Checklist [NGWA-CHECKLIST source note]
Signs it's time to decide
You don't need to wait for the taps to run dry. Penn State Extension lists decreasing pumping rate, decreasing water level, decreasing specific capacity, decreasing total well depth and increasing sand or sediment as warning signs. Penn State Extension: Water Well Maintenance and Rehabilitation When you see them, get a contractor's inspection and yield test before the problem becomes an emergency. Planned work lets you compare quotes, schedule around your household, and choose between rehabilitation, deepening and replacement on evidence rather than in a hurry. How long water wells last explains what typically wears out first. [PSU-REHAB source note]
Common questions
Is it cheaper to deepen a well than drill a new one?
Often, because deepening reuses the existing hole, casing and wellhead. But if the casing is damaged or the well needs extensive repair, a new well can be the better value. Get itemized quotes for both.
Can every well be deepened?
No. The casing diameter, the condition of the well, how it was originally built and local rules all matter. Dug wells and driven wells are generally not deepened the way a drilled well can be. A contractor should inspect the well first.
Will deepening improve my water quality?
It might, or it might make it worse. Water quality depends on the formations the well draws from, and deeper zones can carry more minerals. Test the water after any change to the well.
What happens to the old well if I drill a new one?
It must be decommissioned (plugged and sealed) by a qualified contractor according to state or local rules, so it can't become a path for contamination.
Is it worth deepening a shallow dug well?
Usually not in the way a drilled well is deepened, because dug wells are wide, lined and lack continuous casing. Replacing a failing dug well with a properly cased and grouted drilled well is the more common fix.
How do I know if my well can be deepened?
A contractor needs the well log, the casing diameter and condition, and the current water level. If the casing is sound and nearby wells show water below your current depth, deepening may be practical.
Sources & claim context
Citations mark where guidance is grounded. They are general resources dated on retrieval, not guarantees for any property, project, price, licensure, permit or yield. No expert, attorney or reviewer signoff is claimed by this site.
Penn State Extension: Using Low-Yielding Wells · Penn State Extension · accessed 2026-10-10
https://extension.psu.edu/using-low-yielding-wells
Cost figures in the article are Pennsylvania-era estimates; not quotes
Penn State Extension: Managing Your Well During Drought · Penn State Extension · accessed 2026-10-10
https://extension.psu.edu/managing-your-well-during-drought
Regional guidance; diagnosis needs a professional
Penn State Extension: Water Well Maintenance and Rehabilitation · Penn State Extension · accessed 2026-10-10
https://extension.psu.edu/water-well-maintenance-and-rehabilitation
Inspection-interval advice differs from NGWA annual recommendation
NGWA (Wellowner.org): Homeowner's Maintenance Checklist · NGWA · accessed 2026-10-10
https://wellowner.org/resources/water-well-maintenance/homeowners-well-maintenance-checklist/
Industry guidance; local code governs construction
NGWA (Wellowner.org): Restoring Flow through Water Well Rehabilitation · NGWA · accessed 2026-10-10
https://wellowner.org/resources/water-well-maintenance/restoring-flow/
Results vary; casing breaks or debris can complicate rehabilitation
Claims are grounded in the dated source notes above; project-specific price, yield, licensure and permit answers require site-specific and local verification.