Here's the honest answer up front: you can't literally retrofit a Home Master TMAFC into a tankless system because the TMAFC's whole architecture — the modular sumps, the 2-pass Full Contact alkaline pass, and the slow membrane — is built around a pressurized storage tank. To convert Home Master TMAFC to tankless and reclaim cabinet space, you have two realistic paths in 2026: relocate the bulky 4-gallon tank to a remote spot (basement, adjacent cabinet, garage stub) or replace the TMAFC outright with a true tankless RO unit that produces water on demand. Below is the practical walkthrough, including the tankless alkaline replacements that match what TMAFC owners actually love.
Why You Can't Literally Convert a TMAFC to Tankless
The Home Master TMAFC and TMAFC-ERP are excellent tank-based systems — modular filter housings, a catalytic carbon stage, and patented 2-pass remineralization — but the membrane is rated at roughly 75 GPD under ideal conditions, which translates to a real-world fill rate too slow to dispense on demand. Tankless RO systems get around this by using a much higher-output membrane (typically 400–800 GPD) paired with an internal booster pump, so water leaves the faucet within seconds of opening it. There is no aftermarket kit that turns a TMAFC's 75 GPD membrane and gravity-fed Full Contact stages into an instant-flow tankless rig — the plumbing, electrical, and membrane sizing simply don't line up. So when people say they want to "convert Home Master TMAFC to tankless," what they really want is one of two outcomes: keep the TMAFC but stop losing cabinet real estate to the tank, or step up to a slim tankless replacement that frees the entire footprint.
Path A: Keep the TMAFC, Relocate the Tank
If your TMAFC is producing great water and you don't want to spend another $300–$600, the cheapest cabinet-space fix is simply moving the tank somewhere else. The 4-gallon Home Master tank is a standard 1/4" quick-connect tank, so you can extend the tank tee line with John Guest tubing and place the tank in an adjacent cabinet, under the basement ceiling directly below the sink, or even tucked behind the dishwasher kickplate. Three caveats worth knowing before you start drilling holes:
Tankless RO Comparison for Former TMAFC Owners
| System | GPD | Stages | Pure:Drain | Alkaline? | Power Needed |
|---|---|---|---|---|---|
| Waterdrop G3P600 | 600 | 8 | 2:1 | No | Yes |
| Waterdrop G5P700A | 700 | 8 | 2:1 | Yes (pH+) | Yes |
| Frizzlife PD600-TAM3 | 600 | 5 | 2:1 | Yes (mineral) | Yes |
| Waterdrop T4-A | 450 | 10 | 2:1 | Yes (pH+) | Yes |
| VIOMI V6 Pro | 600 | 9 | 3:1 | Mild minerals | Yes |
| Home Master TMAFC-ERP (reference) | 75 | 7 | 1:1 | Yes (Full Contact) | Yes (ERP only) |
- Pressure drop matters. Every extra foot of 1/4" tubing slightly reduces dispense rate at the faucet. Keep total run under ~15 feet, or step up to 3/8" tubing with a reducer at the faucet.
- Temperature matters. If you're putting the tank in an unheated garage or basement, you risk freeze damage and slow membrane output in winter. Cold water also makes the Full Contact alkaline stage less effective.
- Service access matters. You'll need to bleed the bladder and refresh the air charge every couple of years. Don't bury the tank somewhere you can't reach a Schrader valve.
If a remote tank works in your house, this is the smartest path — you keep the Home Master's Full Contact alkaline taste and just shift the bulk somewhere else. If you'd rather do a head-to-head on the original system, our Home Master TMAFC-ERP vs. APEC ROES-PH75 comparison covers what you'd give up.
Path B: Replace the TMAFC with a True Tankless RO
For most readers searching for how to convert Home Master TMAFC to tankless, the real solution is a swap. A modern tankless unit eliminates the 4-gallon bladder tank entirely, replaces the multi-sump filter bank with stacked cartridges, and uses a built-in booster pump for instant flow. The under-sink footprint shrinks from roughly 16"W × 6"D × 18"H plus a separate tank, to a single appliance about the size of a small wastebasket. You typically reclaim 60–70% of your cabinet floor.
What you'll lose: the TMAFC's iconic 2-pass Full Contact remineralization, which is genuinely one of the best alkaline implementations in the home RO market. What you'll gain: dispense rates 5–10x faster, no annual tank sanitization, no pre-charged bladder to babysit, smart faucets with TDS and filter-life readouts, and modular twist-in cartridges that take seconds to swap. If alkaline taste is non-negotiable, choose a tankless unit that includes a remineralization post-filter — several do, and they're called out below.
What to Look For in a Tankless Replacement
If you're coming from a TMAFC, prioritize these specs over flashy LED faucets:
- Membrane GPD: 400 GPD minimum for a comfortable drink-and-cook household; 600–800 GPD if you have 4+ people or fill pots a lot.
- Pure-to-drain ratio: 2:1 or better. Some budget tankless units waste 3+ gallons per pure gallon — worse than your old TMAFC, which is a 1:1 system.
- Alkaline remineralization stage: If you switched to a TMAFC for the taste, get a tankless with a calcium/magnesium post-filter so you don't downgrade.
- Certification: NSF/ANSI 58 (RO performance) and 372 (lead-free materials) at minimum.
- Cabinet footprint: Measure your under-sink height. Some 800 GPD units are nearly 18" tall.
Top Tankless Replacements for TMAFC Cabinets
Waterdrop G5P700A — Best Alkaline Tankless for TMAFC Loyalists
If you bought the TMAFC specifically for the Full Contact alkaline pass, the Waterdrop G5P700A is the closest analog in the tankless category. It's an 8-stage system with a true pH+ remineralization post-filter, NSF/ANSI 58 and 372 certified, 700 GPD output, and a 2:1 pure-to-drain ratio that almost matches the TMAFC's 1:1 frugality. The chassis is roughly 17" tall and under 6" wide, so it tucks against the rear wall of the cabinet and leaves the entire floor open for cleaning supplies. The smart LED faucet shows filter life and TDS at a glance. Waterdrop G5P700A Alkaline Mineral pH+ Reverse Osmosis Water Filter.
Frizzlife PD600-TAM3 — Best Mineral Profile in a Compact Body
The Frizzlife PD600-TAM3 runs 600 GPD with an alkaline mineral post-filter, NSF/ANSI 58, 53, 42, and 372 certifications, and 2:1 efficiency. It's slightly shorter than the Waterdrop G5 and easier to slot under sinks with garbage disposals. Frizzlife also markets explicit PFAS/PFOA reduction, which TMAFC owners on municipal water often care about. The cartridges are twist-in composite filters, so you no longer wrestle with sump wrenches the way you did with the Home Master. Frizzlife Reverse Osmosis Water Filter.
Waterdrop G3P600 — Best Pure-Performance Pick (No Alkaline)
If you're willing to give up remineralization for a cleaner install and the most user-reviewed tankless on the market, the G3P600 is the obvious choice. NSF/ANSI 42, 53, 58, and 372 certified, 600 GPD, 8-stage filtration, 2:1 efficiency, and a slim profile. You can always add an inline alkaline cartridge downstream for $40 if you miss the TMAFC's mouthfeel. Waterdrop G3P600 Reverse Osmosis System.
Waterdrop T4-A — Best 10-Stage Alkaline With Dual Flow
The T4-A is a 10-stage, 450 GPD tankless system with dual-flow architecture (separate clean lines for drinking and cooking), NSF/ANSI 372 certification, and a pH+ remineralization stage. It's a bit slower at the faucet than the 600+ GPD models but uses less power and runs quieter, which matters in open-concept kitchens where the cabinet sits near a dining area. Waterdrop T4-A Alkaline pH+ Reverse Osmosis Water Filter.
VIOMI V6 Pro — Best Efficiency Numbers
If your water bill matters, the VIOMI V6 Pro hits a 3:1 pure-to-drain ratio — meaning only one gallon goes down the drain for every three you produce. That's better than almost any tankless in this class and noticeably better than older TMAFC units. It's a 9-stage, 600 GPD system with NSF/ANSI 42, 53, 58, and 372 certifications and a smart LED faucet. VIOMI V6 Pro Reverse Osmosis System.
If You Decide to Keep the TMAFC Instead
Plenty of TMAFC owners try a tankless and miss the Full Contact taste enough to come back. If you're on the fence, the current-generation Home Master TMAFC-ERP Artesian Full Contact Reverse Osmosis System uses a permeate pump to push waste ratio down to roughly 1:1, which is still better than nearly every tankless on the market. The cabinet footprint is the real cost — not water efficiency. If you're still weighing the broader category, our best alkaline RO systems roundup lays out the trade-offs.
Installation Reality Check When You Swap
When you remove a TMAFC and install a tankless, you're not just unbolting a tank. Plan for an afternoon and budget for these realities: you'll need a 110V outlet inside the cabinet for the tankless pump (run one if you don't have it), the existing tank-tee under the faucet handles dispense differently than a direct-feed faucet (the tankless faucet replaces the old one), and the drain saddle clamp from the TMAFC may need re-drilling for the new system's smaller waste line. If you're newer to under-sink plumbing, our RO installation walkthrough covers the steps that don't change between brands.
One last thought: don't toss your TMAFC. The sumps and the Full Contact remineralizer have a strong resale market, and the catalytic carbon stage is worth something on its own. Sell it as a complete unit before you commit to a tankless — you'll typically recover $150–$250 toward the new system.
Frequently Asked Questions
Can I just remove the tank from a Home Master TMAFC and run it tankless?
No. The TMAFC membrane only produces about 75 GPD, which is far too slow for on-demand dispense without a tank. The faucet would trickle. The tank isn't optional storage — it's required buffer storage between the slow membrane and your faucet demand. Removing it without a major architecture change just breaks the system.
Is there a Home Master tankless model I could upgrade to instead?
Home Master sells the HydroPerfection and the TMHP series, but as of 2026 they don't market a true tankless on-demand model competing with Waterdrop or VIOMI in the under-sink category. If brand loyalty matters, the TMAFC-ERP with permeate pump is the closest in-family upgrade, but it still uses a tank. For a true tankless conversion, you have to switch brands.
Will a tankless RO taste different than my TMAFC?
Yes, slightly. The TMAFC's 2-pass Full Contact pass is unusually mineral-rich for an RO system. Most tankless units that advertise "alkaline" use a single-pass post-filter, which adds fewer minerals. Choose a tankless with an explicit pH+ or remineralization cartridge (G5P700A, T4-A, Frizzlife PD600-TAM3) to get closest to TMAFC mouthfeel.
How much cabinet space do I actually save by going tankless?
Most TMAFC installs occupy roughly 16"W × 6"D for the filter bank plus a separate ~11" diameter, 15" tall tank. A typical tankless replacement is ~6" wide and 17" tall with no separate tank, so you typically reclaim 60–70% of the under-sink floor. Real numbers vary — measure before you buy.
Do tankless RO systems waste more water than the TMAFC?
Usually yes, but not by much. The TMAFC-ERP is rated 1:1 (one gallon waste per gallon produced), which is essentially the best in the industry. Most tankless units are 2:1, with a few like the VIOMI V6 Pro at 3:1. On a per-household basis, the extra waste is typically a few hundred gallons per year — negligible on city water, more meaningful on well systems with septic.
Do I need to upgrade my drain or shutoff valve when I switch to tankless?
Usually no. The cold-water shutoff and drain saddle from your TMAFC install are reusable. You may need to re-drill the drain saddle if the new system uses 3/8" waste tubing instead of 1/4". The shutoff valve adapter is almost always cross-compatible.
What's the best tankless RO if I want the smallest possible cabinet footprint?
Among current 2026 models, the Waterdrop G3P600 and Frizzlife PD600-TAM3 have the smallest depth at roughly 5.5", letting them sit flush against the cabinet back wall. For a deeper dive into compact picks, see our roundup of the best under-sink RO systems for 2026, which weighs footprint, performance, and price together.
Key Takeaways
- Choosing the right convert Home Master TMAFC to tankless means matching the key features to your specific needs and budget
- Read real customer reviews and check the return policy before you commit
- Also covers: remove TMAFC storage tank
- Also covers: Home Master tankless conversion mod
- Also covers: TMAFC under-sink space saver
- Compare value across models — the priciest option is not always the best fit