Sinkholes, Sand, and Shims: Why Pasco County Mobile Homes Go Out of Level

September 4, 2026

A mobile home in Pasco County goes out of level for one reason far more often than any other: the sand under its piers consolidates and washes, a little every wet season, until the frame no longer sits on one plane. Not a sinkhole. Sand. The Florida Geological Survey’s own database bears that out for the Zephyrhills side of the county, the USDA soil survey explains the mechanism, NOAA’s rainfall normals supply the schedule, and a relevel, $450 to $800 for a singlewide and $750 to $1,400 for a doublewide, is the fix. Here is the whole picture, with the numbers.

Start with the sinkhole question, because everyone does

Pasco is genuinely one of Florida’s sinkhole counties, and it is not useful to pretend otherwise. The Florida Geological Survey keeps a statewide Subsidence Incident Report database, a record of every reported ground collapse or depression since the 1960s. As of its 2026 update it holds 4,443 reports, and Pasco accounts for 344 of them, fourth in the state behind Hillsborough at 617, Marion at 483, and Citrus at 449, ahead of Hernando at 315 and Polk at 304. Fifty-six of Pasco’s reports came in the 2010s and 36 more since 2020. Insurers, lenders, and buyers all know this, and every Pasco homeowner has seen the news footage.

Now sort the same database by town. Hudson leads Pasco with 57 reports. Port Richey has about 50, New Port Richey roughly 36, Holiday 17. Those are all on the west side of the county, along US-19. Land O’ Lakes, in the middle, has ten. Zephyrhills has seven. Dade City has five. Crystal Springs does not appear as a town at all. The karst belt that gives Pasco its reputation runs up the Gulf side; the eastern ridge country where most of the county’s manufactured homes sit is a different story.

That does not mean a sinkhole cannot happen under a Zephyrhills home. It means that when a home on Chancey Road or Gall Boulevard develops a slope, the base rate says sand, and a crew that has been under a few hundred of these homes knows the difference. Ordinary pier settling shows up as a few low piers along one side or one end, dropping gradually over seasons, with the ground surface itself undisturbed. Subsidence looks different: a depression forming in the ground, cracks in the soil, piers dropping fast in a tight circular pattern, sometimes the ground visibly lower around one pier than its neighbors. A crew that sees the second pattern tells you to call a geotechnical professional and does not shim it. A crew that sees the first, which is nearly every time, gives you a pier map and a price.

The sand, specifically

A manufactured home concentrates its whole weight through a few dozen small footings. Florida Rule 15C-1.0102 sets the minimum pier foundation at a 4-inch by 16-inch by 16-inch solid concrete pad and tells installers to assume a soil bearing capacity of 1,000 pounds per square foot unless the local building authority says otherwise. That is under two square feet of contact per pier, each carrying a share of a home that weighs many tons, pressed into whatever the ground happens to be.

Around Zephyrhills, the ground is two kinds of sand.

The ridge sands. The USDA soil survey maps the higher ground east of the county, the ridge that runs up through Zephyrhills to Dade City at 118 feet, as Tavares sand, “ridges on marine terraces,” moderately well drained, and on the knolls Astatula and Candler sands, which NRCS rates excessively drained with a water table deeper than 80 inches. These soils are dry, deep, and loose. A pier pad on them does not sit in water; it sits on sand that packs down under a concentrated load and migrates when rain runs through it. The settling is steady and it is worst wherever roof water is concentrated: under a downspout, at the low corner of a sloped lot.

The flatwoods and depressions. Between the ridges the survey maps Myakka, Pomona, Wauchula, Ona, and Wabasso soils, every one of which NRCS classes as poorly drained, and in the wet depressions the Zephyr series, named for this town, whose type location is a few miles north of SR-54 and which NRCS describes as “ponded for 6 months or more in most years.” A pier pad on this ground sits in saturated sand for weeks at a stretch every summer, and saturated sand carries less load than dry sand. The pier on the wettest spot drops first.

Either way, the pattern inside the house is the same. One pier drops a half inch, the I-beam above it deflects, the wall above that leans by a fraction of a degree, and the door opening in that wall stops being a rectangle. Doors are precise objects; they report it first. Then windows bind, then a crack opens over a doorway, then the floor develops a slope you can feel in your socks, then on a doublewide the marriage line opens at the ceiling, then the skirting bows as the home comes down onto it.

The rain, on schedule

NOAA’s 1991 to 2020 climate normals for the St. Leo cooperative station, about nine miles northwest of Zephyrhills, put annual precipitation at 52.48 inches. Of that, 32.37 inches falls in June through September: 7.18 in June, 8.35 in July, 9.33 in August, 7.51 in September. That is 62 percent of the year’s water in a third of the year, almost all of it in afternoon thunderstorms that drop an inch or two in an hour, run off the roof, out the downspout, and under the skirting. November, by contrast, normals at 1.61 inches.

So the piers move in summer, and the symptoms get noticed in fall. In a town where local park operators describe the population roughly doubling between November and April, a lot of the noticing happens in the first week back, when the front door of a home that sat empty over a wet summer will not latch. That is why October is the busiest month for level checks in Zephyrhills, and why the snowbird handoff is worth its own post.

And every few years the rain comes all at once. Milton in October 2024 put 11 to 15 inches on gauges from Zephyrhills to Wesley Chapel to Dade City, per the National Hurricane Center’s report, two weeks after Helene had already soaked the county. Ground that saturated lets piers sink faster in a month than in a normal year, and the crews are still finding Milton’s fingerprints on first-time surveys.

The shims, and why the fix is periodic

A relevel is a measured process. The crew shoots every pier with a water level against a datum pier and gets a number per pier. Twenty-ton bottle jacks on solid cribbing lift the low sections in small increments across several stations, never one corner cranked to grade, which is what cracks drywall. Each low pier is rebuilt: blocks re-stacked, crushed caps and pads replaced, hardwood shims driven tight in opposing pairs between the cap and the beam. HUD’s installation standard limits how much shim and lumber can stack on top of a pier, so a pier that would need a tall stack gets rebuilt at the right height instead. Then the whole frame is re-shot, every pier is checked by hand for load, and the anchor straps, slack after any settling, are re-tensioned. The mobile home leveling page walks through it step by step.

Here is the honest part. On this sand, that relevel is maintenance, not a cure. Unless the reason the ground under a pier is wet gets fixed, the downspout moved, the low corner graded, the pad rebuilt on compacted ground, the same pier drops again. Three to five years is the normal interval on a home in a graded park lot with decent drainage. A low lot, an owned-land home nobody ever graded, or a home freshly set on unprepared ground shortens it. A well-drained pad on the ridge stretches it. A good crew points out the downspout while it is under there, because a $500 relevel on schedule is a far better deal than a $1,500 relevel with pier rebuilds after ten years of neglect.

Who is allowed to do this

Section 320.8249 of the Florida Statutes requires anyone who installs a mobile home to hold a mobile home installer license from the Florida Department of Highway Safety and Motor Vehicles, and blocking, leveling, and anchoring a sited home is installation work under Rule 15C-1. That includes a routine relevel in a Zephyrhills park. All work arranged through us is performed by licensed, insured local mobile home installers. The under-home fingerprints of the alternative, shim stacks past the HUD limit, scrap-lumber caps, a corner jacked until the ceiling split, are what licensed crews spend half their time undoing.

The bottom line

If your Pasco County mobile home has developed a sticking door or a slope, the ground has almost certainly done what the soil survey says it does. Not a sinkhole; sand and rain, on the schedule NOAA publishes. The fix is a day’s work at a published price, the level check that tells you exactly what your home needs is free, and the crew will tell you straight if what they see under there is the rare other thing. Book the check, or read the FAQ first.