My house uses city water. For the most part it is clean and tastes fine, but I can see mineral build up in toilets and elsewhere.

I started to research whole house systems with 1-6 types of filters. I also looked at systems with 1-3 filters you could place at a specific sink/tap.

My thought was that for my kitchen sink water, from which we drink, I would want the most filtering, but for bathrooms/appliances I might need less intensive/types of filters.

Therefore, I thought maybe there was a good strategy to say at the pipe from the city water I install these types of filters then at the kitchen sink I also install some more specific or additional filters. My goals would be better tasting water for drinking (but not necessarily tooth brushing) and to prolong life of washing machine, water heater, etc. by reducing metals, etc. I also figured that over time, it would save money to use fewer types of filters for the whole house and then only use more hardcore/specific types of filters where we actually drink.

Is this something that makes sense? It is better to just do a big multi stage system at the water intake? If it does make sense (looking at 20 year payback period) then how should I setup this system and what types of filters where? Not looking for a hardcore reverse osmosis system, but willing to spend around $500-750 initial cost (not including labor if I need to hire a plumber/installer for the main system) with less than $50-100 a year in ongoing costs.

  • Costs are something you'll have to figure locally. Cost in NYC is going to be different than in Bugtussle.
    – FreeMan
    Commented Jul 7, 2021 at 15:45
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    I would post a full answer, sharing my own experience with filter systems, but...well, the real issue here is a completely unrealistic budget. It's not clear what mineral build-up you are having trouble with -- you'll need a water test to be sure, but probably it's just hard water (calcium and magnesium) -- but you're either going to spend big up front or spend big on ongoing costs. You can't do it for cheap for both. I think you've already got a couple of decent answers to tell you that, so whatever else I could offer won't help much without a budget change. Commented Jul 8, 2021 at 7:28

4 Answers 4


To tell the truth to filter out the mineral deposits from your city water on everything it will normally cost many times that of replacing your devices.

You can meet the cost restraints with a single sink location but to do the entire home it will cost many times 100/ year operating cost.

  • Thanks for the perspective. I received ads in the mail for a whole house system around $1-2K USD and have seen systems online around $500. If the annual cost is going to be a few hundred a year for "filters", then it sounds like it might not be worth it for the whole house and to just focus on drinking water. I am not considering RO systems, though "something" might be useful if balanced with cost.
    – HelpEric
    Commented Jul 8, 2021 at 15:54
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    Eric the difference in an RO system is you pay almost everything up front other than the system flushing that uses a lot of water to clean the membranes. So although these type of systems are more costly to install the pre / string filter is all that is needed to be changed and on city water it could be fine for 6 months or longer.
    – Ed Beal
    Commented Jul 8, 2021 at 16:09

WOW, a lot to sort out there. My water supply is a well that very high TDS (total dissolved solids), such as iron, magnesium, sodium, as well as hydrogen sulfide. I have a water softener (not just a filter) system system that does a good job making the water usable. It's a whole house system and we have reverse osmosis for just the Instant Hot, Ice Maker and a separate tap for cool water in the kitchen. RO systems are generally pretty low capacity.

There are lots of types of "filters" and the term is often misused. You best bet is to have your water tested and figure out exactly what you're dealing with and then design the best filter system (maybe just a filter, maybe active carbon, maybe an actual water softener that uses salt, or an RO filter in critical places).

In designing your system, are there outdoor spigots used for irrigation, car washing, etc.? Softened water usually contains a lot of sodium chloride (salt) that isn't good for plants, also, why would anyone want to treat that water anyway? The minerals (TDS) are actually good for plants. So I have 2 lines from the well, one is softened, the other is untreated and used for irrigation.

EDIT: In re-reading my answer it sounds pretty self absorbed, sorry, still on my first cup of coffee this AM. To answer your last question, I hate to say it, but your budget is very limited, I think my system cost about $8K 15 years ago. I don't know what you mean by a "payback period" in this case. I'm familiar with the term, but just don't don't know how'd you calculate it? ....less frequent appliance/sink/toilet replacement?

You will have operating and maintenance costs even possibly replacement costs over that time period. So that'll be a hard calc. to make.

  • Thanks for the explanation. I will get the water tested and then see what fits and then scout options from there. Is your $8k system a RO? I've seen a few less intensive systems where its just a series of chambers/filters. e.g., a single chamber under sink for under $100 initial cost. Payback being less frequent replacement of appliances or value versus buying bottled water jugs, etc. But we just received the annual water report and the water is safe to drink, so may be better to just save towards new appliances.
    – HelpEric
    Commented Jul 8, 2021 at 15:57
  • No, I'm not sure, but I don't think RO is practical or cost effective for the whole house. In my first paragraph I mentioned that our small RO device is just for the Instant Hot, ice maker and a small extra spigot. I think it has a very small pressure tank (maybe 2 gallons). The dishwasher and sink main supply are not attached to the RO, only the softened water, like the rest of the house. Commented Jul 8, 2021 at 16:08
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    Also, bear in mind that nearly all water softeners/treatment systems usually involve salt tanks that require continued feeding of bags of salt. I'm not talking a small bag here. Salt for these are sold at HD and Lowes in about 40lb bags, every couple of months I get about 10-12 bags (400+ lbs) to feed the softener. And when they cycle it dumps a bunch of highly salty water. If you direct that to any lawn or landscaping area, you'll kill it. I direct mine to a storm-water catch basin. Commented Jul 8, 2021 at 16:15
  • Having the salt water discharge directed away from plants is a good idea. Also if you have a salt system and have heart problems having an RO system for drinking water is just about a must have, or change to potassium but it is way more expensive than salt (the cost differential pays for the RO).
    – Ed Beal
    Commented Jul 9, 2021 at 16:13

Whole house filtering may not be possible in every situation

As it turns out, there are some houses these days where "whole house" water filtering or softening is impossible. This is because of a combination of factors:

  • water filters and especially water softeners can restrict raw flow rates in the incoming water supply,
  • NFPA 13D/IRC P2904 fire sprinklers can be implemented as multipurpose systems that combine fire sprinklers and domestic cold water supply together (this is done to reduce risks caused by water stagnation in the fire sprinkler system as well as save on plumbing costs),
  • and fire sprinklers need the full flow available to them to function properly (a typical residential fire sprinkler head is rated for around 12GPM, which is a lot beefier than a showerhead even!).

So, if you have a multipurpose fire sprinkler system, then you'll need to use more localized solutions for domestic water treatment.

  • Good information for general; in my case I have a separate set of plumbing and intake from the sprinklers.
    – HelpEric
    Commented May 4 at 0:30

To treat mineral buildup, I recommend a water softener. Rather than treating the whole house water supply, I suggest treating only the hot water (upstream of the hot water heater) and the cold water supply for the washing machine. Your outside spigots and irrigation system typically only use cold water. My arrangement keeps softened water out of those systems. In the shower and at sinks, mixing softened hot water and unsoftened cold water will reduce the hardness. This helps with sudsing and rinsing. For the dishwasher, hot water only means all the water is softened. Washing machine needs softened cold water in addition to softened hot water so the wash and rinse is 100% softened. The question of water quality for drinking is handled separately. I installed a filter upstream of my refrigerator. If I add a hot/cold drinking water tap at the kitchen sink, that too will require a filter.

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