Why the First 30 Days Matter

A water purifier that is incorrectly set up in the first month will underperform from day one — and you may not know it. New filter media need proper flushing. The storage tank needs to be correctly pre-charged. The UV lamp needs to be running and verified. A baseline TDS measurement needs to be taken so you have a reference point to track membrane performance over time.

Most purifier owners do none of these things. They turn on the unit, draw a glass of water and assume everything is fine. This checklist ensures your purifier is correctly commissioned and that you have the information you need to maintain it effectively.

Day 1 — Installation Verification

Confirm All Tube Connections Are Secure

Before running the purifier for the first time, trace every tube connection. Each push-fit connection should be confirmed by:

  • Pushing the tube firmly until it bottoms out in the fitting
  • Tugging the tube — it should not pull out without pressing the release collar

Check connections at: sediment housing inlet, sediment to carbon, carbon to membrane housing, membrane permeate to tank, tank to ASO valve, ASO to UV, UV to post-carbon, post-carbon to faucet. Check the drain connection at the drain saddle.

Check Tank Pre-Charge Pressure

Use a standard tyre pressure gauge on the Schrader valve at the base of the storage tank. The tank should be pre-charged to 7–8 PSI. If it reads zero, use a bicycle pump or tyre inflator to charge it. Do not exceed 10 PSI.

A tank with incorrect pressure will either fail to fill (too high pressure) or result in continuous pump running (too low pressure).

Turn On the Inlet Water Supply

Open the saddle valve on the cold water supply line. Listen for the pump to start — this confirms the system is pressurised and functioning. Watch all connections for 5 minutes. Any drip means a connection needs to be re-seated or tightened.

Days 1–3 — The Mandatory Flushing Period

Why Flushing Is Non-Negotiable

New filter media contain:

  • Carbon fines (small black particles from carbon block manufacturing)
  • Preservative solutions (some RO membranes are shipped wet in a preservative solution)
  • Manufacturing dust from filter housings
  • Trapped air from assembly

None of these are toxic in small quantities, but the taste is unpleasant and you should not consume the first tank volumes.

The Flushing Protocol

First tank: Open the purified water faucet and let the entire first tank drain completely. This may take 4–6 hours depending on your membrane speed. Discard this water — pour it into the sink.

Second tank: Fill and drain completely. The water may still have slight carbon taste or slight discolouration from carbon fines.

Third tank: Fill, run one glass and taste. If the taste is clean and there are no black particles visible, the system is ready for use. If particles or strong taste remain, flush one more tank volume.

Total flushing water: 25–40 litres. This is a one-time investment for a system that will produce safe drinking water for years.

Day 3 — Baseline Testing and Recording

Test and Record Your Source Water TDS

Fill a glass from your regular kitchen tap (bypassing the purifier). Measure with your TDS meter and record the reading. This is your Feed TDS baseline — the reference number for calculating membrane rejection rate for the entire life of the purifier.

Example: Feed TDS = 420 ppm

Test and Record Your Purified Water TDS

Fill a glass from the purifier faucet. Measure and record. This is your Day 1 Permeate TDS.

Example: Day 1 Permeate TDS = 22 ppm

Calculate and Record Your Initial Rejection Rate

Rejection rate = (1 - 22/420) x 100 = 94.8%

Write this number on a piece of paper and stick it inside the cabinet, or note it in your phone. This is your membrane's baseline performance. When this number drops significantly (below 85%), it is time to replace the membrane. You cannot know when the membrane is failing without this baseline reference.

Label Each Filter With the Installation Date

Use a permanent marker to write today's date directly on each filter housing or on a sticker on each housing. This tells you at a glance how old each filter is and when it is due for replacement:

  • Sediment filter: replace at 3 months from today's date
  • Pre-carbon filter: replace at 6 months
  • RO membrane: test at 12 months, replace when rejection drops below 85%
  • UV lamp: replace at 12 months
  • Post-carbon filter: replace at 12 months

Photograph the Installation

Take a clear photograph of the complete installed system showing all tube connections, filter positions and the tank. If you ever need to call a technician or replace a component, this photograph saves significant time in explaining the configuration.

Week 2 — Establish Your Monitoring Routine

Set Up Monthly TDS Testing Reminders

Set a recurring reminder on your phone — the first of each month — to test your purified water TDS. The test takes 2 minutes. Record the reading alongside the date. Over 12–24 months, this creates a trend that tells you exactly when your membrane is aging and needs replacement, rather than finding out when it has already failed.

Verify UV Lamp Operation

The UV lamp indicator light (usually blue or purple) should be permanently illuminated when the purifier is powered. Check this weekly — particularly important because a failed UV lamp provides zero microbial protection while appearing to function normally.

Test Water Flow Rate

Fill a 1-litre container from the purified water faucet and time it. Record the time. This is your baseline flow rate. A significant slowing of flow rate over the coming months indicates pre-filter clogging or membrane fouling — catching this early allows you to address it before it becomes a problem.

Months 1–3 — Building Maintenance Habits

Schedule the 3-Month Sediment Filter Change

Three months from installation day — if you live in an area with iron-rich or turbid water — your sediment filter may be nearing the end of its useful life. Visually inspect it (if the housing is transparent) by holding it up to a light. If it is dark orange or brown, change it regardless of calendar date.

Find Your Local Filter Supplier

In the first month of ownership, locate:

  • Where to buy compatible sediment, carbon and post-carbon filters locally (hardware stores, purifier service centres, online)
  • Prices for compatible generic filters vs branded filters
  • The phone number of at least two local purifier service technicians

Having this information before you need it means you will not face a delay when a filter needs urgent replacement.

Read Your Purifier Manual

This sounds obvious but most purifier manuals are never read. Spend 20 minutes with the manual in the first month and note:

  • The exact filter model numbers for your specific unit
  • The manufacturer's recommended service schedule
  • The warranty terms and what voids the warranty
  • The manufacturer's customer service number for Bangladesh

30-Day Completion Checklist

By the end of your first month, you should have:

  • Flushed a minimum of 3 full tank volumes before first use
  • Recorded baseline Feed TDS and Permeate TDS with rejection rate
  • Labelled every filter housing with installation date and replacement due date
  • Set monthly TDS testing reminders on your phone
  • Verified UV lamp is operational
  • Located local filter suppliers and noted prices
  • Photographed the installation
  • Noted first sediment filter change date (3–6 months from today)

A purifier that is correctly commissioned and monitored from day one will serve your family with safe, clean water for 5–8 years without major issues. A purifier that is installed and forgotten is a ticking clock toward unsafe water — the only question is when the filters fail, not if.