Best Portable Water Softeners for RVs and Campers
Quick answer: for most RVs, a 16,000-grain portable softener like the On The Go Double Standard is the sweet spot. On The Go’s own table puts it at about 1,066 gallons of soft water at 15 grains per gallon (gpg) before you recharge it with two boxes of table salt, and it needs no electricity or tools. Small campers and vans can get by with an 8,000-grain unit, while park models and tiny houses may want a bigger one. To estimate any portable softener, divide its grain rating by your water’s hardness, or use the calculator below.
Our picks:
- Best overall: On The Go Double Standard (16,000 grains)
- Best for small campers and vans: On The Go Standard (8,000 grains)
- Best with a filter-and-recharge kit: PRO+AQUA WS-P-16 plus its regeneration kit
- Best for park models and tiny houses: On The Go Park Model
How we chose: we haven’t tested these softeners ourselves. We compared capacity, recharge steps, size, flow and warranty using the makers’ own pages and manual, and favored brands that publish clear capacity tables and instructions.
How many gallons will a portable softener give you?
A portable softener holds a fixed amount of hardness, measured in grains. Divide that by your water’s hardness in grains per gallon and you get roughly how many gallons of soft water it makes before it needs recharging. That’s the method behind On The Go’s own capacity tables:
| Water hardness | 8,000 grains (Standard) | 16,000 grains (Double Standard) | Park Model |
|---|---|---|---|
| 5 gpg | 1,600 gal | 3,200 gal | 5,760 gal |
| 7 gpg | 1,142 gal | 2,285 gal | 4,115 gal |
| 11 gpg | 727 gal | 1,454 gal | 2,615 gal |
| 15 gpg | 533 gal | 1,066 gal | 1,920 gal |
| 25 gpg | 320 gal | 640 gal | 1,150 gal |
| 58 gpg | 137 gal | 275 gal | 495 gal |
Gallons of soft water per recharge, from On The Go’s capacity tables for each model.
Campground water varies from park to park, so test it when you arrive. On The Go includes hardness test strips with its softeners. On the U.S. Geological Survey’s scale, water above about 7 gpg (121 mg/L) is hard and above about 10.5 gpg (180 mg/L) is very hard.
RV water softener recharge calculator
See how many gallons you’ll get between recharges, and how much salt to pack for a trip.
Enter your water hardness to see how long a charge lasts.
How to recharge (regenerate) an RV water softener
Recharging, also called regenerating, flushes the hardness out of the softener’s resin with salty water. Here’s On The Go’s method for its Double Standard, with Standard and Park Model amounts in brackets. Other brands work in a similar way, so follow your own manual.
- Turn off the water and disconnect the outlet hose.
- Drain the softener by tilting it or turning it upside down, with the cap on.
- Remove the top cap and add two full 26-oz boxes of table salt (Standard: one box; Park Model: four). You can pour it in dry, mix it with warm water first, or pour it slowly while adding water.
- Replace the cap, turn the water on and rinse very slowly, with a stream about the width of a pencil, for 24–30 minutes (Standard: 12–15; Park Model: 50–60).
- Turn the flow up to a fast rinse for 6–8 minutes (Standard: 3–4; Park Model: 10–12).
- Test the output with a hardness strip. It should read soft (0–3 gpg) and shouldn’t taste salty.
The rinse water is salty, so drain it where your campground allows. For extremely hard water, On The Go suggests adding a little Super Iron Out along with the salt (2–4 teaspoons for the Double Standard). If the water still tastes salty after a recharge, rinse longer; see why softened water can taste salty.
First use, back-flushing and storage
- First use: no salt is needed. Stand the softener upright and flush it for 4–6 minutes (Standard: 2–3; Park Model: 7–9) before connecting it to your RV.
- Back-flush every 3 months: connect the water to the softener’s outlet with the included adapter and run it for 5–10 minutes (Standard: 2–5; Park Model: 10–15). If you’re also recharging, back-flush first.
- Storage: recharge, then drain the water out, but never dump out the resin. After a long break, On The Go recommends sanitizing the softener, flushing it and recharging it before use.
Connect the softener between the campground faucet and your RV’s city-water inlet with drinking-water-safe hose. On The Go’s warranty doesn’t cover alterations such as changing the fittings to hook it up inside a shower.
Our picks
| On The Go Double Standard | On The Go Standard | PRO+AQUA WS-P-16 with kit | On The Go Park Model | |
|---|---|---|---|---|
| Capacity | 16,000 grains | 8,000 grains | 16,000 grains | 28,800 grains |
| Gallons at 15 gpg | 1,066 | 533 | About 1,066 (16,000 ÷ 15) | 1,920 |
| Salt per recharge | Two 26-oz boxes | One 26-oz box | 2 boxes, using its kit | Four 26-oz boxes |
| Flow | 3 gpm | 2 gpm | Not listed | Not listed |
| Size | 22 × 9.5 in | 22 × 6.75 in | 10 × 10 × 20 in | 8.75 × 48 in |
| Weight | 32 lb | 18 lb | 35 lb | 50 lb (shipping) |
| Warranty | 1 year | 1 year | 1 year, or 3 if you register | 1 year |
On The Go Double Standard (OTG4-DBLSOFT)
The Double Standard is the 16,000-grain version of On The Go’s portable softener, assembled in Indiana according to its Amazon listing. It’s big enough for most RVs and longer trips, and small enough for a storage bay. Recharging takes two boxes of table salt and no tools.
- Capacity: 16,000 grains; 1,066 gallons at 15 gpg, per On The Go’s table
- Recharge: two 26-oz boxes of table salt, then about 30–38 minutes of rinsing (per the manual)
- Flow: 3 gpm
- Size and weight: 22 inches tall, 9.5 inches across, 32 lb
- Includes: hardness test strips, back-flush adapter, 4-foot drinking-water hose, storage caps, handle and cradle base
- Warranty: 1-year limited
Good to know: On The Go’s warranty requires buying from an authorized dealer, so check who the seller is (or ask On The Go) before you buy. There’s also a version with brass fittings (OTG4-VM-DBLSOFT).
Check price on AmazonOn The Go Standard (OTG4-StdSoft)
Half the capacity of the Double Standard in a slimmer, lighter tank. The Standard suits small trailers, vans and weekend trips, or water that’s only moderately hard.
- Capacity: 8,000 grains; 533 gallons at 15 gpg, per On The Go’s table
- Recharge: one 26-oz box of table salt, then about 15–19 minutes of rinsing (per the manual)
- Flow: 2 gpm
- Size and weight: 22 inches tall, 6.75 inches across, 18 lb
- Warranty: 1-year limited
Good to know: its 2 gpm flow is lower than the Double Standard’s 3 gpm, and on hard water you’ll recharge twice as often.
Check price on AmazonPRO+AQUA WS-P-16 plus its regeneration kit
PRO+AQUA pairs its 16,000-grain portable softener with a Pre-Filter Regeneration Kit (WS-P-REG-KIT), a sediment-and-carbon filter housing plus the parts used for recharging. PRO+AQUA sells the two as a bundle on its own site; on Amazon in October 2026 they were separate listings. PRO+AQUA says a full recharge with the kit takes 2 boxes of common table salt and under 30 minutes.
- Capacity: 16,000 grains
- Recharge: uses the regeneration kit; 2 boxes of table salt
- Size and weight: softener 10 × 10 × 20 inches, 35 lb; kit 7 × 7 × 14 inches, 3 lb
- Bundle includes (PRO+AQUA’s site): protective cover, Y-splitter and shut-off valves, adapters, a 1/4-inch brine hose and a filter wrench
- Warranty: 1 year, extended to 3 years when you register it
Good to know: PRO+AQUA’s page doesn’t list a flow rate, and the tank is heavier than On The Go’s 16,000-grain unit. On Amazon, add the regeneration kit (WS-P-REG-KIT) separately.
Check price on AmazonOn The Go Park Model
On The Go’s largest portable softener, sold with a salt dispenser so you can recharge it without pouring salt straight into the tank. At 48 inches tall it’s meant for park model RVs, tiny houses and marinas rather than a storage bay.
- Capacity: 28,800 grains, per its Amazon listing; 1,920 gallons at 15 gpg in On The Go’s table
- Recharge: four 26-oz boxes of table salt, then about 60–72 minutes of rinsing (per the manual)
- Size and weight: 8.75 inches wide, 48 inches tall; 50 lb shipping weight
- Warranty: 1-year limited
Good to know: its Amazon listing showed as unavailable when we checked, so buy it from On The Go’s own site.
See it at On The GoFrequently asked questions
Do I need a water softener for my RV?
If the water where you camp is hard, a softener cuts the spots and scale it leaves on fixtures, glass and inside your water heater. Test the water with a strip: on the USGS scale, anything above about 7 gpg counts as hard.
How often do I need to recharge an RV water softener?
When it has used up its capacity. Divide the grain rating by your hardness to get gallons per charge: a 16,000-grain unit on 15 gpg water lasts about 1,066 gallons. Test the output with strips and recharge when it stops reading soft.
What salt does a portable water softener use?
Ordinary table salt. On The Go and PRO+AQUA both measure it in boxes of common table salt, and On The Go’s manual specifies 26-oz boxes.
Can I use a portable water softener for a hot tub or an apartment?
On The Go markets its softeners for spas and hot tubs as well as RVs; check your hot tub manual for the water hardness it recommends before filling. In an apartment, a portable softener needs a hose connection and somewhere to drain salty rinse water, so look at our guide to small water softeners instead.
How long does the resin last?
On The Go sells resin refill kits, and one retailer lists a 7–10 year lifespan for the Double Standard. On The Go’s manual says to back-flush every 3 months and to recharge and drain the softener before storing it.
Related guides
- Best water softeners (all types)
- What size water softener do you need? (for homes)
- Best small water softeners
- Why does softened water taste salty?
- How much does a water softener cost?
Sources
- On The Go, product pages for the Double Standard, Double Standard (brass), Standard and Park Model (specs and capacity tables), and its warranty.
- On The Go, Portable Water Softener user manual (first use, recharging, back-flushing and storage).
- PRO+AQUA, WS-P-16 softener and WS-P-16-BNDL bundle.
- RV Upgrade Store, On The Go Double Standard listing (lifespan).
- U.S. Geological Survey, water hardness scale.