Salt Level Keeps Dropping in Your Salt Pool?

Quick Reality Check: Salt vs Evaporation

Evaporation takes water out of the pool, not salt. When water leaves as vapor, the salt stays
behind and the remaining water actually becomes more concentrated, not less.

That means a salt level that keeps dropping — without big drains or backwashing — usually means
salted water is physically leaving the pool through:

• Backwashing or draining to waste
• Heavy splash-out and overflow
• A leak in the shell, plumbing, or equipment area

Normal Ways Salt Leaves a Pool

Even with no leak, salt can drop slowly over time. Common causes include:

• Backwashing or draining water out of the pool — Every gallon you send to waste takes salt with it.
• Heavy splash-out from swimmers and water features — Cannonballs, dogs, and deck jets can move more water than you think.
• Overflow during big rain events — If the pool has spilled over the edge or into an overflow line, salted water has left.

All of these send salted water out of the system. If you recently backwashed a lot, lowered the pool, or had
storms with overflow, a modest, gradual salt drop can be normal.

When a Falling Salt Level Starts to Look Like a Leak

A leak becomes more likely when:

• You haven’t done significant draining or backwashing.
• There’s no recent storm or regular overflow situation.
• You’re not seeing huge splash-out or water features running all day.
• Your salt level keeps falling much faster than it should.

If your salt is dialed in one week and badly low the next, with no obvious reason, that means salted water is
leaving somewhere — through the shell, plumbing, or equipment.

➜ If you also suspect a water-level issue, see:
Autofill Never Shuts Off? How to Tell If It’s Hiding a Leak.

Step 1: Make Sure Your Readings Are Trustworthy

Before you chase leaks, make sure the salt readings themselves are solid. Bad data = bad diagnosis.

• Compare methods: Check salt with at least two methods — strips, a drop test, or a
  digital salt meter. They should be in the same ballpark.
• Consider the cell’s reading: Your salt system’s control panel may read differently than a
  strip or meter, especially if the cell is scaled or older.
• Clean the cell if needed: Heavy scale on the cell plates can cause incorrect low-salt
  readings, even if the actual salt level is fine.

If independent tests (strip/meter) agree that salt is dropping, it’s time to look at where the salted water is
going.

Step 2: Look for Obvious Salt-Water Loss

Next, check the “easy” places salted water might be leaving:

• Backwash / waste line: Is there any trickle from the backwash hose or waste line while the
  valve is in normal filter mode?
• Equipment pad: Is the pad constantly wet or are there
  slow drips or sprays from unions, valves, filter, or heater connections?
• Overflow area: After heavy rain, does water regularly spill out of an overflow drain or over
  the coping?
• Heavy use: Have you had a run of big pool parties, kids and dogs in the pool, or features
  running for hours every day?

If one of these clearly lines up with when the salt started dropping, you may be dealing with heavy
normal loss rather than a hidden leak.

Step 3: Double-Check with a Bucket Test and Salt Meter

To confirm what’s really going on, combine water-loss testing with salt tracking:

1. Run a bucket test for pool leaks to see if the pool is losing more
   water than weather alone.
2. Use a reliable salt test (strip, drop kit, or digital meter) to track salt level over
   1–2 weeks.
3. Keep notes on any backwashing, draining, big swim parties, or storms during that time.

What the combo tells you:

• Bucket test is normal, small salt drop: Likely occasional splash-out, rain overflow, or
  routine maintenance (normal).
• Bucket test points toward a leak + salt keeps dropping fast with no good explanation:
  Strong sign that salted water is leaking out through the shell, plumbing, or equipment.

Step 4: Watch Your Autofill and Water Bill

A leak plus an autofill is the perfect storm for crashing salt levels. The leak lets salted water out; the
autofill replaces it with fresh, unsalted water. Over time, your salt level slides lower and lower.

Watch for signs like:

• Autofill running or trickling almost every time you walk by.
• A water bill that’s clearly higher than usual for the season.
• A waterline that always looks “perfect” even though salt keeps dropping.

➜ For more detail, see:
Autofill Never Shuts Off? How to Tell If It’s Hiding a Leak.

When to Treat It as a Leak and Call a Pro

It’s time to treat the situation as a likely leak and consider leak detection when you see a combination of:

• Consistent water loss beyond normal evaporation on a bucket test.
• Salt readings that fall quickly even without backwashing, draining, or heavy splash-out.
• An autofill that runs often and/or a higher-than-normal water bill.
• Other leak clues like damp areas, soft soil, or a wet equipment pad.

A proper leak detection visit will focus on where salted water is leaving the system so you’re not guessing,
over-salting, and paying for water you never get to swim in.

Bottom Line

A salt level that drifts slowly over months can be normal. A salt level that keeps crashing, even when you’re
not draining or backwashing, usually means salted water is leaving the pool somewhere it shouldn’t.

By verifying your readings, checking obvious loss points, running a bucket test, and watching your autofill and
water bill, you can tell whether you’re dealing with simple maintenance and splash-out—or a leak that’s quietly
washing money and salt out of your pool.

Next:

Do I Really Have a Pool Leak? 7 Checks Before You Call a Leak Company