Installation Step-by-Step: Under-Sink Purification System

Installation Step-by-Step: Under-Sink Purification System

Why install an under-sink water purification system?

Under-sink water purification systems deliver high-quality drinking water at the point of use without taking up countertop space. They remove sediments, chlorine, taste and odor, and — with advanced options like reverse osmosis (RO) or ultraviolet (UV) — reduce dissolved solids, microbes, and other contaminants. For homeowners and businesses looking to improve water quality, an under-sink system is a cost-effective and convenient solution.

About Aqualitek and our authority in water purification system solutions

Aqualitek Water Treatment Technologies Co., Ltd. (AQT) manufactures advanced water purification systems and high-quality components for residential, commercial, and industrial use. With engineering expertise and global manufacturing operations based in Guangzhou, China, Aqualitek provides customized, reliable solutions and technical support to help you select and install the right under-sink water purification system.

Before you start: Choose the right under-sink water purification system

Selecting the correct system affects installation complexity and performance. Common types include sediment+activated carbon filters, ultrafiltration (UF), reverse osmosis (RO), and systems with UV disinfection. Consider feed water quality, flow needs, space under the sink, water pressure, and maintenance preferences. Typical under-sink RO systems need 40–80 psi and often include a small storage tank (2–4 gallons) for steady delivery.

Tools and materials you will need for installation

Prepare tools and supplies before beginning. For most under-sink water purification system installs you will need: adjustable wrench, drill with appropriate bits, Phillips/flat screwdriver, tubing cutter or sharp utility knife, plumber's tape (Teflon tape), bucket, towel, and safety glasses. Include any manufacturer-supplied fittings, filter cartridges, tubing, faucet, saddle valve or feed adapter, and mounting brackets. Always use the fittings and parts recommended by the manufacturer to maintain warranty and system performance.

Safety and pre-installation checks for your water purification system

Turn off the cold-water supply to the sink and open the existing faucet to relieve pressure. Verify electrical requirements if your system includes a UV lamp or booster pump — ensure a nearby grounded outlet and follow appliance safety codes. Inspect under-sink space for leaks, corrosion, or electrical hazards. If unsure about plumbing or electrical work, hire a licensed professional to avoid damage or code violations.

Step 1 — Mount the filter housing and components

Start by positioning the filter housings, bracket, and optional tank under the sink in a layout that allows easy access for cartridge replacement. Mark and drill pilot holes where the bracket will attach to the cabinet wall. Use stainless screws supplied with the system. Secure the bracket and hang the filter housings. For RO systems, mount the storage tank horizontally or vertically with the valve at the top for safe pressure operation.

Step 2 — Install the dedicated faucet

If your system includes a dedicated drinking-water faucet, choose an unobstructed location on the sink or countertop. Many sinks have unused holes for accessories; otherwise you may need to drill a hole (follow sink manufacturer recommendations). Insert the faucet shank, secure with the provided nut, and connect the faucet tubing but do not tighten until final alignment. Use plumber's tape on threaded connections to prevent leaks.

Step 3 — Connect to the cold-water feed

Shut off the main cold-water valve. Disconnect the cold water supply line to the sink faucet. Use the included feed adapter or saddle valve to connect the system's inlet to the cold-water line. Many kits provide a brass T-fitting or a self-piercing saddle valve; T-fittings screwed to the shutoff valve are more reliable long-term. Reconnect the cold supply and tighten with an adjustable wrench, ensuring there are no cross-connections to hot water.

Step 4 — Plumb tubing between components

Measure and cut tubing to connect the inlet, filter housings, optional RO membrane housing, storage tank, and faucet. Use quick-connect fittings supplied with the system for secure, tool-free connections. Ensure tubing is routed without kinks and avoid sharp bends. For RO systems, note the labeled lines: feed, reject (drain), tank, and faucet. Secure tubing with clips to prevent strain and vibration.

Step 5 — Install drain connection (RO and systems with reject water)

Reverse osmosis systems produce a reject stream that must be disposed of to the drain. Use the included drain saddle or a dedicated drain adapter. Choose a drainpipe location above the P-trap and below the sink basin. Clean the pipe surface, clamp the saddle, and drill the small hole as instructed. Insert the reject tubing into the saddle fitting and secure. Ensure the drain line slopes downward and is not submerged to prevent backflow.

Step 6 — Connect electrical (if required)

If your water purification system includes a UV lamp or booster pump, plug the unit into a grounded outlet using the provided cord. Do not use extension cords for continuous operation. For UV lamps, ensure the lamp is grounded and the lamp enclosure is dry and properly sealed. Follow the manufacturer's electrical safety instructions exactly to maintain safety and warranty coverage.

Step 7 — Initial system flush and leak check

With all connections made, open the cold-water supply slowly and inspect all fittings for leaks. Tighten fittings as needed. For cartridge-based systems, replace protective caps and open the system valves as instructed. For RO systems, allow the tank to fill (this may take 1–3 hours depending on feed pressure) and then flush the tank once full by opening the faucet and letting water run until the tank is drained. Discard the first tankful to remove manufacturing residues and protect taste.

Step 8 — Test water quality and flow

After flushing, test the water at the faucet. Check taste, clarity, and flow rate. For RO systems, measure total dissolved solids (TDS) with a handheld TDS meter to confirm performance — expect a 95–99% reduction for typical RO membranes. Check pressure at the faucet: under-sink systems with storage tanks commonly deliver 0.5–1.5 GPM (gallons per minute). If results are outside expected ranges, review tubing routing, flow restrictor, and pressure conditions.

Routine maintenance to keep your water purification system performing

Scheduled maintenance ensures system longevity and water safety. Typical intervals: sediment and carbon prefilters every 6–12 months, RO membrane replacement roughly every 2–3 years (depending on feed water quality), UV lamp annually, and post-filters every 6–12 months. Check manufacturer guidance and keep a maintenance log. Replace filters with genuine parts from your supplier — Aqualitek components meet performance specifications and compatibility requirements.

Troubleshooting common installation issues

If you see leaks, identify the source and tighten or re-seat fittings. Low flow can indicate clogged prefilters, low feed pressure, closed shutoff, or a faulty tank bladder. Continuous drain flow on an RO unit often means the membrane or flow restrictor is damaged. If you detect unusual taste or odor after installation, re-flush the system and replace the post-filter if necessary. For electrical problems with UV units, confirm outlet power and bulb seating; replace the UV lamp if the indicator shows failure.

Performance comparison: common under-sink water purification system types

Choosing the right technology depends on contaminants you want to remove. The table below summarizes capabilities and typical application notes for each technology.

Cost of ownership and efficiency considerations for your water purification system

Total cost includes purchase price, installation (DIY vs professional), replacement filters, electricity (for UV or pumps), and water waste (for RO). Typical RO wastewater ratios vary by model: older systems 3–4:1 (waste:product) while modern high-efficiency units can be 1–2:1 or use permeate pumps to reduce waste. Consider lifecycle cost and environmental impact when choosing a system.

Warranty, certification, and E‑E‑A‑T considerations

Choose systems with credible third-party certifications (e.g., NSF/ANSI 42, 53, 58) relevant to performance claims. Maintain installation records and use certified replacement parts to preserve warranties. Aqualitek supports product documentation and certification details to meet Google’s E‑E‑A‑T expectations by offering transparent technical data, real-world performance, and manufacturer-backed warranties.

When to call a professional installer

Hire a licensed plumber or water-treatment specialist if your installation requires modifying supply lines, drilling through stone countertops, adding permanent electrical connections, or integrating with whole-house systems. Professionals ensure compliance with local codes and deliver reliable long-term performance for your water purification system.

Checklist: quick post-install actions for your water purification system

1. Verify no leaks after 24 hours. 2. Discard initial tankful(s) or first 5–10 gallons post-install. 3. Record filter replacement dates. 4. Test TDS or microbiological indicators if applicable. 5. Register product warranty with the manufacturer (Aqualitek recommends storing purchase and installation records).

FAQs — Common user questions about under-sink water purification systems

Q: How long does installation take?
A: Typical DIY installations take 45–120 minutes depending on system type and do-it-yourself skill level. RO systems usually require longer due to tank filling and drain connection.

Q: How often should I change filters?
A: Prefilters and carbon cartridges: 6–12 months. RO membranes: 2–3 years. UV lamps: annually. Replace according to usage and feed water quality.

Q: Will an under-sink system remove lead and fluoride?
A: RO systems and certain certified media can reduce lead and fluoride. Always check product certification (e.g., NSF/ANSI standards) for specific contaminant reduction claims.

Q: Can I install the system myself?
A: Yes, many homeowners install under-sink systems. Follow manufacturer instructions and local plumbing codes. For complex plumbing or electrical work, consult a professional.

Q: Does RO waste a lot of water?
A: Waste ratios vary by design. Modern high-efficiency RO units and permeate pumps can reduce waste to about 1–2:1 (waste:product). Consider systems with higher efficiency if water conservation is a priority.

Q: How do I check if the system is working?
A: Measure TDS for RO, test microbial indicators after UV, and monitor taste and flow. Many problems are detectable by reduced flow or change in water taste.

Need help selecting or installing?
Aqualitek offers technical support, certified parts, and installation guidance for residential and commercial under-sink water purification systems. Contact us for product specifications, certification documents, and local professional installer recommendations.