Well water in Marion County is usually hard. In USGS samples from 122 Marion County wells, the typical well measured about 150 mg/L of hardness, roughly 9 grains per gallon, and 45 of the 122 were above 180 mg/L, the USGS line for very hard water. Iron was low in most of the wells the USGS sampled, but about 1 in 10 were above the EPA guideline of 0.3 mg/L. Hard water and iron leave scale on pump parts and clog screens, and hydrogen sulfide, where it is present, corrodes metal parts faster. The data below shows what Marion County well owners can expect and how often to service a well system. For well drilling and pump services in Ocala, see our well drilling and pump services in Ocala page.
Marion County Well Water Chemistry: USGS Data Summary
The U.S. Geological Survey has sampled wells across Marion County since the 1950s. Its results are public through the Water Quality Portal. The table below summarizes every USGS sample for Marion County wells in the portal, 1955 to 2015. Each well counts once, at the median of its own samples, so a well sampled many times does not skew the result.
Most of these samples are decades old, and they come from wells the USGS chose to sample, not from a survey of private wells. Your well may vary with depth, casing, and the zone it draws from. A lab water test is the only way to know what your well actually contains.
| Parameter | USGS Result (Marion County wells) | Impact on Well Service | Source |
|---|---|---|---|
| Hardness (as CaCO3) | Median 150 mg/L (about 9 gpg); middle half 110 to 244 mg/L; 45 of 122 wells above 180 mg/L (very hard) | Scale builds on pump parts and fittings; shortens service life | USGS via Water Quality Portal (CSV); USGS hardness scale |
| Iron | Median about 0.02 mg/L; 10 of 103 wells above 0.3 mg/L | Above 0.3 mg/L (EPA secondary guideline) iron stains fixtures and fouls screens and pump parts | USGS via Water Quality Portal (CSV); EPA secondary standards |
| pH | Median 7.6; middle half 7.3 to 7.8 (122 wells) | Higher pH favors scale buildup; affects iron treatment systems | USGS via Water Quality Portal (CSV) |
| Well depth | Median 100 ft; middle half about 65 to 183 ft (165 wells with a recorded depth) | Deeper wells take more time and equipment to service | USGS well records via Water Quality Portal (CSV) |
USGS samples from 1955 to 2015, retrieved from the Water Quality Portal on September 29, 2026. Iron samples with no detectable iron are counted as zero.
What High Hardness and Iron Mean for Pump Service Life
Hard water is hard on pump equipment. Where hardness runs above 180 mg/L, as it did in more than a third of the Marion County wells the USGS sampled, mineral scale builds on pump parts if the water is untreated. Scale forces the pump to work harder to push the same flow. It draws more power and runs hotter. Over time, that shortens motor life.
Iron in well water can feed iron bacteria. These bacteria form rust-colored deposits inside the pipe and on intake screens. The deposits block flow and force the pump to work harder. That can cause short-cycling, which burns out the motor. Iron bacteria are not a health hazard, but they speed up pump failure. For iron and sulfur treatment before water enters the home, see the iron and sulfur well water treatment guide for Ocala.
Karst Limestone and Well Permits in Marion County
Florida's limestone and dolomite dissolve slowly in slightly acidic water. The Florida Geological Survey calls the result karst: caves, springs, sinkholes and underground drainage. Drilling through karst needs careful casing and grouting. The driller must seal the hole through void zones to keep surface water out of the aquifer. Florida rule 62-532 sets the permit and construction standards for water wells.
Marion County is split between two water management districts, the St. Johns River district and the Southwest Florida district. Both have delegated well construction permits for most private wells in the county to the Marion County Health Department. Under Florida rule 62-532.400, a permit is needed before building, repairing or abandoning a well. A water use permit is a different, separate permit for larger withdrawals. Florida law does not require one for domestic use by individual users (section 373.219, Florida Statutes). For drilling context, see our well drilling and pump services in Ocala page.
Recommended Service Intervals for Marion County Well Owners
The table below shows the service intervals we recommend for the water conditions Marion County wells commonly have. Test your own water to see which rows apply to you.
| Condition | Recommended Service Check | Why |
|---|---|---|
| Hardness above 180 mg/L (very hard, about 10.5 gpg) | Annual pump inspection | Scale builds on pump parts and fittings; check flow rate and amp draw |
| Iron above 1 mg/L | Semi-annual pump check | Iron fouls screens and pump parts; iron bacteria clog drop pipe and cut flow |
| H2S present (detectable odor) | Inspect motor at 5 to 7 years of service | H2S corrodes metal parts and speeds up motor wear |
| New well, or an existing well with no casing record | Pre-drill site check; confirm casing log on existing wells | In karst, void zones need proper casing and grout to block surface water |
These are our service recommendations, not agency rules. Individual well conditions vary; test your water before making treatment or service decisions.
What to Expect from a Well Service Call in Ocala
Every service call starts above ground. We check the pressure gauge, pump cycle, switch contacts, pressure tank, and all valves we can reach. Most no-water and low-pressure calls are solved at this stage without pulling the pump. For Marion County wells, we also look for scale at the tank inlet, mineral deposits on fittings, and any discoloration from iron bacteria.
When the problem is below ground, we pull the drop pipe to inspect the pump, valve, and wiring. Deeper wells need a hoist and more labor time. We quote the pull after we confirm the above-ground side is clear. For what a pump repair visit covers, see our pump repair in Ocala page.
When to Call a Licensed Well Contractor in Ocala
Call a Florida well contractor right away if you notice any of these signs:
- No water or a big drop in pressure with no change in how you use water
- Pump running without building to cut-off pressure
- Red, orange, or black color in your tap water
- Rotten-egg odor that is new or getting worse
- Pump short-cycling (turning on and off fast)
- Water heater failing sooner than expected (scale buildup)
- Any well more than five years old with no recent water quality test
Quality Filters and Pumps LLC holds Florida Water Well Contractor License #7494. We are a family-owned company in Lake County and have served Central Florida homes, businesses, and farms for more than 15 years. Call (352) 771-2325 or visit the contact page to schedule.