Home › Refrigerator Water Filters › LG › LRSC21951ST
Water Filter for the LG LRSC21951ST (LT500P)
✓ 100% compatible — no bypass plug needed
🔧 5-min push-in swap
🇺🇸 Ships from Indiana
Every cartridge that fits this model — pulled live from the catalogue:
✓
LRSC21951ST specifics — where the filter actually lives
The filter bay on the LRSC21951ST inside the fresh-food cavity, position varying with dispenser spec, a deliberate placement that keeps the swap away from the door seals and drawer rails. Mechanically the LRSC21951ST uses a push-and-twist cartridge: the short locking turn after the press is what keeps the seal honest between changes.
The recurring owner notes: keep a folded towel under the bay before you open it; the line holds a cup of water even with the valve shut. Under the cabinet differences one thing holds: the LRSC21951ST shares its water path with the whole LT500P generation — the cartridge is the common denominator, not the door count. The ST tail marks finish variants of one chassis; the filter bay is shared across the entire finish range.
Reading the LRSC21951ST model code — what the digits tell you
The two digits after the letters are the cabinet size: this is a 21 cubic feet refrigerator, which sets how much dispenser work the cartridge does between changes. Hold this constant while shopping: whatever the door count, the cartridge answer for this chassis is the LT500P family.
Swap it in 5 minutes
- Press the release (if fitted), twist the old cartridge free, and pull it from the header.
- Wet the new cartridge’s o-ring with cold tap water so it seats without dragging.
- Push the cartridge square onto the header, then give it the locking quarter turn.
- Run two gallons through the dispenser to flush carbon fines, then hold the filter-reset control until the status light clears.
What this filter takes out of your water
| What it targets | Standard that covers it |
|---|---|
| Chlorine taste & odor | NSF/ANSI 42 — aesthetic effects |
| Particulates, Class I | NSF/ANSI 42 — fine sediment |
| Lead | NSF/ANSI 53 — health effects |
| Cysts (cryptosporidium, giardia) | NSF/ANSI 53 — microbial |
| PFOA & PFOS | NSF/ANSI 53 (P473) — varies by cartridge |
Coverage above lists what the standard addresses, not a performance claim for any specific cartridge — removal claims vary by certificate, so check the NSF listing for the exact part number you are buying.
LRSC21951ST filter questions
How do I reset the filter light on the LG LRSC21951ST?
With the new cartridge seated, press and hold the filter reset until the light clears — panel placement differs, so the LRSC21951ST manual’s filter section has the exact control for your trim.
Running the LRSC21951ST with an empty filter bay — does it need a cap?
No — the LT500P bay seals on the cartridge itself, so removing it just means unfiltered water until the next change, not a leak.
Are off-brand filters safe for a LG refrigerator?
Certified aftermarket cartridges are built to the same NSF test standards as the OEM part, and federal warranty law (Magnuson-Moss) protects your coverage when you use them.
Why is the OEM LT500P cartridge so much more expensive?
Part of the OEM price is the badge and the distribution chain. Certified alternatives meet the same test standards at a lower unit price, especially in multi-packs.
How often should I replace the filter in my LRSC21951ST?
Every six months or at the rated gallon capacity, whichever comes first — the LT500P class cartridges all share that service interval.
Do I need to turn off the water supply to change it?
No — the bay is designed for a live swap. Expect a small dribble, keep a towel in reach, and flush a couple of gallons through the new cartridge before the first glass.
Every filter that fits your fridge
This bay takes the OEM LT500P. ClearFit verified-fit alternatives for this exact slot are being staged — every compatible option for your fridge is one lookup away.
Check every filter that fits →This filter expires six months from today
Your HVAC filter is probably on a different cycle. Track them all in one place.
months until this filter should be replaced (200-gal rated life)
Free tool · tracks fridge + HVAC + whole-house · auto-refill optional
More models using this filter
Related guides
POPULAR GUIDE
How to change a Whirlpool refrigerator water filter
Every Filter 1–6 bay location — including the door-mounted bays on WRX models, with door-open angles and cap-release quirks. — read the guide →
POPULAR GUIDE
How to reset your Whirlpool filter light
Filter 1–6 indicator maps showing which key actually clears the light on your panel. — read the guide →
WATER PROBLEM GUIDE
Does your fridge filter remove fluoride?
What EDR1RXD1-class carbon blocks actually take out — and the systems that do remove fluoride. — read the guide →