Waterdrop TSU vs TSA Under Sink Filters: Which Is Better? (October 2026)
Choose the TSU if you want a separate faucet and a 24-month UF filter; choose the TSA for direct faucet connection and longer stated system capacity. Neither reduces TDS, and both are designed for municipal cold water.
On this page (9 sections)
- Waterdrop TSU vs TSA: what is the main difference?
- Which one is easier to install with your faucet?
- How do filtration and flow compare?
- Which filter schedule is easier to manage?
- Which system fits a small cabinet?
- Who should choose the Waterdrop TSU?
- Who should choose the Waterdrop TSA or WD-TSA-UF?
- What should you know about minerals and water quality?
- Which Waterdrop under sink filter should you pick?
Choose the TSU if you want a separate faucet and a 24-month UF filter; choose the TSA for a direct faucet connection and higher stated maximum flow. In this Waterdrop TSU vs TSA comparison, both systems are for municipal cold water and neither reduces TDS.
The main decision is how you want filtered water delivered. The TSU comes with its own faucet, so installation requires drilling the countertop; the TSA connects to a compatible existing faucet and does not include another faucet.
The WD-TSA-UF is a third option if you want a direct connection plus a 0.01 micron ultrafiltration membrane. It shares the TSA's listed maximum flow rate, while its filtration stages and replacement schedule differ.
Waterdrop TSU vs TSA: what is the main difference?
The TSU is a separate-faucet ultrafiltration system, while the TSA is a direct-connect filter with no separate faucet. That installation choice is likely to matter before small differences in flow or filter schedule.
The TSU has a 3-stage system and a 0.01 micron ultrafiltration membrane. It retains minerals, does not reduce TDS, and is described as requiring countertop drilling for its included faucet.
The TSA connects directly to compatible faucets with 1/2 or 3/8 inch female NPT threads. It uses 3 filters for 8-stage filtration, retains minerals and does not reduce TDS.
The best under sink water filters guide covers other non-RO options if neither faucet setup fits your kitchen. For a broader decision about filtration styles, see our under sink reverse osmosis buyer's guide.
Does the Waterdrop TSU vs TSA comparison include a third choice?
The WD-TSA-UF is worth considering if you want direct faucet connection and a UF membrane. It uses 3 compact filters for 9-stage filtration and includes a 0.01 micron ultrafiltration membrane.
Like the TSA, it has a stated maximum flow rate of 1.5 GPM and connects to compatible faucets. It also retains minerals and does not reduce TDS, so it is not a reverse osmosis system.
Which one is easier to install with your faucet?
The TSA and WD-TSA-UF are simpler choices if you want to keep your existing faucet and it has compatible threads. The TSU makes sense when you prefer a dedicated filtered-water faucet and can drill the countertop.
The TSU is designed for standard under-sink cold-water connections and includes a brushed nickel faucet. Its installation needs a countertop opening for that faucet, so confirm the surface can be drilled and choose a location with enough room underneath.
The TSA and WD-TSA-UF connect directly to compatible faucets. Their guidance names 1/2 and 3/8 inch female NPT threads; quick-connect faucets may need an adapter, so confirm compatibility before ordering.
All 3 systems are intended for cold water, not hot water. The TSA and WD-TSA-UF call for pre-filtration when used with well water, while the TSU is not suitable for well water.
Does the TSA include a separate faucet?
No, the TSA and WD-TSA-UF do not include a separate faucet. They are designed to send filtered water through a compatible existing faucet.
That keeps the countertop setup simpler, but makes faucet compatibility part of the decision. If your faucet uses a quick-connect fitting or another thread type, check whether an adapter is available for your setup.
The TSU includes a separate faucet. If your sink already has a spare opening, you may be able to use it; otherwise, drilling is part of the installation plan.
How do filtration and flow compare?
Choose the TSU for its 0.01 micron membrane and the TSA for a higher stated maximum flow rate. The TSA is listed at up to 1.5 GPM, while the TSU is listed at up to 1.05 GPM.
Those are maximum figures, not a promise of the flow you will get at your sink. Water pressure, plumbing and filter condition can affect the stream, and the TSA's guidance says its deep filtration can flow more slowly than untreated tap water.
The TSA uses 3 filters for 8-stage filtration and is described as helping reduce PFAS, PFOA/PFOS, fluoride, chlorine, sediment and other substances. The WD-TSA-UF uses 3 compact filters for 9-stage filtration and adds a 0.01 micron ultrafiltration membrane.
The TSU uses 3 stages, including its 0.01 micron UF membrane. Its stated target substances include chlorine, PFAS, taste, odor and heavy metals.
These systems don't reduce TDS. If your goal is to lower dissolved solids, compare them with reverse osmosis options in our under sink reverse osmosis system guide.
Is the WD-TSA-UF the same as the TSA?
No, the WD-TSA-UF has an ultrafiltration membrane, while the TSA uses a different filter setup. Both connect directly to compatible faucets, retain minerals and have a stated maximum flow of 1.5 GPM.
The WD-TSA-UF lists a 0.01 micron membrane and 9-stage filtration. The TSA lists 8-stage filtration, including a resin stage that helps reduce fluoride.
Choose between them based on whether the UF membrane matters to you and which replacement schedule you prefer. Don't assume their cartridges are interchangeable; use the replacement filters specified for the exact model.
Which filter schedule is easier to manage?
The TSU has the longest stated UF filter interval, while the TSA and WD-TSA-UF spread replacements across 3 stages. Your water quality and usage can affect how often filters need attention.
The TSU's PP filter is scheduled for 6 months, its CT filter for 12 months, and its UF filter for 24 months. The system also has a panel with 4 lights to indicate when filters need changing.
The TSA's three filters are listed at 6 months, 8–12 months and 12–18 months. The WD-TSA-UF uses a 6-month 10PP filter, an 8–12-month 10GC filter and a 10UF filter lasting up to 12 months.
The TSA and WD-TSA-UF use twist-and-lock replacement filters. If you want a simple reminder for routine care, our guide on how to change an under sink water filter cartridge explains the basic process.
Before choosing, check which replacement cartridges match the exact model. The systems use different filter names and model-specific replacements.
Which system fits a small cabinet?
The TSA and WD-TSA-UF have smaller stated dimensions than the TSU. The TSA models measure 12.9 x 4.3 x 12.4 inches, while the TSU measures 14.81 x 4.68 x 13.97 inches.
Measure the cabinet space around the disposal, plumbing and stored items before choosing. Leave room to reach the filter housings and shutoff valve, and follow the model's installation instructions.
A smaller cabinet body does not automatically mean a better fit. The TSU also needs space for its separate faucet tubing and the countertop opening, while the direct-connect TSA models need a compatible faucet connection.
Who should choose the Waterdrop TSU?
Choose the TSU if you want its own faucet, a 0.01 micron UF membrane and a longer stated UF filter interval. It is a better fit when drilling is acceptable and you use municipal cold water.
Its separate brushed nickel faucet keeps filtered water distinct from the main tap. The 24-month UF interval may also suit someone who wants fewer membrane changes, though the PP and CT filters still have shorter schedules.
Skip the TSU if you cannot or do not want to drill the countertop. It also does not suit well water, and its maximum stated flow is lower than the TSA models.
Who should choose the Waterdrop TSA or WD-TSA-UF?
Choose the TSA if you want direct connection, 8-stage filtration and no separate faucet; choose the WD-TSA-UF if a 0.01 micron membrane is a priority. Both need a compatible faucet and municipal cold water, or pre-filtration for well water where applicable.
The TSA is a straightforward choice if fluoride reduction and direct connection match your needs. The WD-TSA-UF adds ultrafiltration while keeping the same listed maximum flow rate and compact dimensions.
Neither model reduces TDS, and neither includes a separate faucet. Check thread compatibility and replacement cartridge names before deciding.
What should you know about minerals and water quality?
None of these 3 filters lowers TDS, because they retain dissolved minerals. A TDS meter reading therefore isn't a complete measure of whether a particular contaminant is present.
The TSU, TSA and WD-TSA-UF are not reverse osmosis systems. If reducing TDS is a main goal, compare the different process and maintenance needs in our tank vs tankless reverse osmosis comparison.
Water quality varies by source. If you have a specific concern, use a suitable water test and check that the system's stated reductions match the contaminant you need to address.
Which Waterdrop under sink filter should you pick?
Pick the TSU for a dedicated faucet and longer UF filter life, the TSA for direct connection without a UF membrane, or the WD-TSA-UF for direct-connect ultrafiltration. First confirm your water source, faucet threads and willingness to drill.
If you use well water, the TSU is not a fit; the TSA models call for pre-filtration. For more choices in this category, see our under sink water filters for well water guide.
Frequently asked questions
Does the Waterdrop TSU or TSA reduce TDS?
No. The TSU, TSA and WD-TSA-UF retain dissolved minerals, so they are not designed to lower total dissolved solids.
A TDS reading alone does not show whether specific contaminants are present; choose filtration based on the water concerns you need to address.
Which Waterdrop filter needs countertop drilling?
The TSU includes a separate faucet and requires countertop drilling. The TSA and WD-TSA-UF connect directly to compatible faucets and do not include a separate faucet, so check the faucet threads before choosing either direct-connect model.
Can I use these Waterdrop filters with well water?
The TSU is not suitable for well water. The TSA and WD-TSA-UF are designed for municipal water, and their guidance calls for pre-filtration if you use well water; check the water source and any required treatment before installation.
Which Waterdrop under sink filter has the longest UF filter life?
The TSU's UF filter has a stated 24-month lifespan, with its other filters scheduled at 6 and 12 months. The WD-TSA-UF's UF filter lasts up to 12 months, while the TSA uses a different three-filter schedule without a UF stage.
