Sediment in water

[David Meiland]

Before I say anything else, let me say that I know I need to get the water tested and will do so. It's geographically inconvenient and therefore has not happened yet.

Anyway, we are on a well that produces plenty of good water. However, it appears to have a fair amount of sediment in it. I recently removed a 2.5-year-old 40-gallon water heater and could hardly drain it due to sediment buildup at the bottom. I finally hauled it out with a hand truck and laid it on its side. An impressive amount of sediment gushed out the fill pipe and onto the deck. Prior to this the unit had been grumbling and slamming quite a bit during firing, so I knew there was a problem. FWIW the unit was removed in order to be replaced with a tankless.

Now, the pressure tank is in the crawl space. It's a 119-gallon Amtrol (?) and it's laying on it's side. The well driller, a man of great reputation and also my neighbor, told me this would be fine. The unit is designed to stand upright, or so it appears, and the inlet/outlet pipe would be at the bottom if it were. As it is, the inlet/outlet pipe is sticking out the end of the tank, exactly half way up.

So, I have some questions. I assume the pressure tank is slowly filling with sediment. There are no noticeable problems with performance, we have the right pressure, we get lots of water between cycles, etc. But since the water heater tank was filling with sediment I assume the pressure tank is too.

I'd like to install some sort of coarse particle filter on the water line (see opening statement re water testing). The usual install seems to be on the downstream side of the pressure tank. What about something upstream? Folks I have talked to have not addressed this. The usual deal seems to be that you notice a decrease in pressure and know to change the filter media. If the filter is upstream the pump is the only thing that will notice the change. Anyway, it seems like a filter would be a good idea--protect the pressure tank, protect the new tankle$$ water heater, protect the other fixtures, etc.

Comments appreciated. Are there things I can do to maintain the pressure tank in this situation, i.e drain it, or something else? Any suggestions on approaches to filtering? Anything else? I had city water for the first 40 years of my life, so this is new stuff.

[Bob NH]

There are differences of opinion on whether the filter should be after the tank or between the pump and the tank. If the filter is after the tank you sacrifice some pressure at higher flow rates.

If the filter is before the tank, then you need to assure that the filter gets changed. Also, you need to put a relief valve before the filter if you have a submersible pump, and maybe a second pressure switch with a bit of refinement of the control circuit.

You should find out if the sediment is coming from the well or if it is being precipitated in the water heater. If you have hard water then there is a good chance that it is precipitate. One way to check that is to see if the material will dissolve in vinegar. If it is sand it won't dissolve. If it is carbonate or calcium sulfate such as you get in a teakettle with hard water, then it will dissolve with warm vinegar.

If you put in a filter, then I recommend a large filter, such as the double length "big blue" size which is 4.5" diameter and 20 inches long. You would need pressure gauges on the inlet and outlet of the filter.

[Gary Slusser]

As long as your water is clear, "sediment" in a pressure tank is not a problem; drain and flush it once a year when you check/adjust the captive air precharge air pressure.

You need to know the type of "sediment"; yours sounds like hard water scale which is normal with hard water. In an oil or gas fired water heater, there can be a substantial buildup of scale inches thick and very deep. It is a killer of those types of water heaters while substantially increasing the cost to heat water and the recovery time/rate of the heater. Water hardness precipitates out of the water when the water is heated and it attaches itself to the hot surfaces inside the tank (bottom and flue pipe) where it traps moisture which then converts to steam causing popping sounds as the steam explodes. That breaks the 'glass' lining exposing the mild steel of the tank to moisture which causes rusting and eventual tank failure.

If you want to complicate your life and risk loss of the submersible pump down the well or a blown drop pipe, put any type or size filter, in any configuration, between a submersible pump and its controlling pressure switch. And if you get creative and install another pressure switch before the filter before the pressure tank, don't forget to install an expansion tank there too or you can cause the pump to cycle on/off constantly while using water; otherwise you will cause excessive water hammer. That cycling kills pump motors and increases the electric bill.

Let us know what the water analysis shows.

[David Meiland]

Thanks for the great replies, gentlemen.

I'll be able to get some water to the lab within a couple of weeks. The only signs of 'scale' I have noticed are some whitish stains on the pinholes on the shower head. There does not seem to be reduction in flow anywhere in the house, and the kitchen sink faucet is probably 20 years old. We don't have rust stains anywhere. I've completely replumbed the house and did not notice anything in the old piping I removed, which was mostly PVC/CPVC with a little bit of old galv. I've made a few mods to copper piping that I installed and never noticed anything inside.

Anyway, I'll report back on the lab work, and warnings re the pump and a filter install are duly noted. I'll have the well guy set that up if I do anything.

[Gary Slusser]

Thanks for the great replies, gentlemen.

I'll be able to get some water to the lab within a couple of weeks. The only signs of 'scale' I have noticed are some whitish stains on the pinholes on the shower head. There does not seem to be reduction in flow anywhere in the house, and the kitchen sink faucet is probably 20 years old. We don't have rust stains anywhere. I've completely replumbed the house and did not notice anything in the old piping I removed, which was mostly PVC/CPVC with a little bit of old galv. I've made a few mods to copper piping that I installed and never noticed anything inside.

Anyway, I'll report back on the lab work, and warnings re the pump and a filter install are duly noted. I'll have the well guy set that up if I do anything.

The whitish stuff on the shower head is either hardness scale, evidence of high sulfates, TDS or chlorides. It isn't sediment. All can cause scale buildup in a water heater and you'll not know of it until you replace the heater and it is much heavier than it should be or you can't drain it out the drain valve; as you've found. In most cases, scale does not form in water lines and it is rare when it forms in valves but... it forms on surfaces where the water is allowed to evaporate; like your shower head.

"Sediment" rarely forms in water lines unless the water contains iron, manganese or H2S and it precipitates (converts to oxides) in the lines due to sufficient DO (dissolved oxygen) content or there is IRB (iron reducing bacteria) in the water. Since you didn't find any "sediment" in your old plumbing, you've proved you have no need for this filter before the pressure tank...

That new tank less water heater will scale up quite quickly if you have hard water. Check your manual and it should mention the problems hard water causes. You can find a DIY water test kit at most hardware stores or swimming pool places.

Any well driller, pump guy or pump supply house folks will say no filter between a submersible pump and its pressure switch.